8-K

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities and Exchange Act of 1934

Date of Report (Date of earliest event reported)       June 13, 2001      

F.N.B. CORPORATION

(Exact name of registrant as specified in its charter)

Florida	0-8144	25-1255406
(State or other jurisdiction of incorporation)	(Commission File Number)	(IRS Employer Identification No.)

F.N.B. Center, 2150 Goodlette Road North, Naples, Florida	34102
(Address of principal executive offices)	(Zip Code)

Registrant’s telephone number, including area code       (941) 262-7600      

(Former name or former address, if changed since last report)

Item 5. Other Events.

     On June 14, 2001, F.N.B. Corporation (“FNB”) and Promistar Financial Corporation (“Promistar”) announced that they had entered into an Agreement and Plan of Merger (the “Merger Agreement”), dated as of June 13, 2001, pursuant to which FNB will acquire Promistar through the merger of Promistar with and into FNB. Under the terms of the Merger Agreement, at the effective time of the merger, each outstanding share of the Promistar’s common stock will be converted into the right to receive 0.926 shares of FNB common stock.

     The merger is intended to constitute a tax-free reorganization under the Internal Revenue Code of 1986, as amended (except for any cash paid to a Promistar shareholder in lieu of a fractional share of FNB common stock), and to be accounted for as a pooling of interests.

     Consummation of the merger is subject to various conditions, including: (i) approval of the Merger Agreement by the shareholders of FNB and Promistar; (ii) receipt of certain regulatory approvals from the Board of Governors of the Federal Reserve System and other federal and state regulatory authorities; (iii) the receipt of an opinion of counsel as to the tax-free nature of certain aspects of the merger; (iv) receipt of a letter from FNB’s independent accountants confirming that the merger may be accounted for as a pooling of interests; and (v) satisfaction of certain other conditions.

     In connection with the Merger Agreement, FNB and Promistar entered into a Stock Option Agreement, dated as of June 13, 2001, pursuant to which FNB has the right, under certain circumstances, to purchase from Promistar a number of shares of Promistar common stock equal to 19.9% of the number of issued and outstanding shares of Promistar common stock, at a price equal to $17.306 per share.

     The preceding description of certain terms of the Merger Agreement and the Stock Option Agreement is qualified in its entirety by reference to the Merger Agreement and the Stock Option Agreement, each of which is included as an exhibit to this report and incorporated into this Item 5 by reference.

     The press release jointly issued by FNB and Promistar announcing the merger is included as an exhibit to this report and is incorporated into this Item 5 by reference.

     The Merger is expected to be consummated during the first quarter of 2002.

Item 7. Financial Statements and Exhibits.

(c) Exhibits.

     The following exhibits are filed with this report:

*2.1	Agreement and Plan of Merger, dated as of June 13, 2001, by and between FNB and Promistar
10.1	Stock Option Agreement, dated as of June 13, 2001, by and between FNB and Promistar
99.1	Press Release issued jointly by FNB and Promistar on June 14, 2001.

* The exhibits to the Agreement and Plan of Merger are omitted from this filing. FNB agrees to supplementally furnish to the Commission upon request a copy of any such exhibit.

SIGNATURES

     Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this Current Report on Form 8-K to be signed on its behalf by the undersigned hereunto duly authorized.

		F.N.B. CORPORATION
	By:	/s/ John D. Waters
		John D. Waters Vice President and Chief Financial Officer
Dated: June 14, 2001

EXHIBIT INDEX

Exhibit
Number	Description of Exhibit
2.1	Agreement and Plan of Merger, dated as of June 13, 2001, by and between FNB and Promistar
10.1	Stock Option Agreement, dated as of June 13, 2001, by and between FNB and Promistar
99.1	Press Release issued jointly by FNB and Promistar on June 14, 2001

EX-2.1

   1

                                                                    EXHIBIT 2.1

                          AGREEMENT AND PLAN OF MERGER
                                 BY AND BETWEEN
                               F.N.B. CORPORATION
                                      AND
                        PROMISTAR FINANCIAL CORPORATION

                           DATED AS OF JUNE 13, 2001


   2

                                TABLE OF CONTENTS



                                                                                       PAGE
                                                                                       ----

                                                                                    
PREAMBLE 1

ARTICLE 1 TRANSACTIONS AND TERMS OF MERGER...............................................1
         1.1      Merger.................................................................1
         1.2      Time and Place of Closing..............................................2
         1.3      Effective Time.........................................................2
         1.4      Execution of Stock Option Agreement....................................2

ARTICLE 2 TERMS OF MERGER................................................................2
         2.1      Articles of Incorporation..............................................2
         2.2      Bylaws.................................................................2
         2.3      FNB Board of Directors.................................................2
         2.4      First National Bank of Pennsylvania Board of Directors.................3

ARTICLE 3 MANNER OF CONVERTING SHARES....................................................3
         3.1      Conversion of Shares...................................................3
         3.2      Anti-Dilution Provisions...............................................3
         3.3      Shares Held by Promistar or FNB........................................3
         3.4      Fractional Shares......................................................3
         3.5      Treatment of Options and Warrants......................................4

ARTICLE 4 EXCHANGE OF SHARES.............................................................5
         4.1      Exchange Procedures....................................................5
         4.2      Rights of Former Promistar Shareholders................................5

ARTICLE 5 REPRESENTATIONS AND WARRANTIES OF PROMISTAR....................................6
         5.1      Organization, Standing, and Power......................................6
         5.2      Authority; No Breach by Agreement......................................6
         5.3      Capital Stock..........................................................7
         5.4      Promistar Subsidiaries.................................................7
         5.5      SEC Filings; Financial Statements......................................8
         5.6      Absence of Certain Changes or Events...................................9
         5.7      Tax Matters............................................................9
         5.8      Compliance With Laws...................................................9
         5.9      Assets................................................................10
         5.10     Legal Proceedings.....................................................10
         5.11     Reports...............................................................10
         5.12     Statements True and Correct...........................................11
         5.13     Accounting, Tax and Regulatory Matters................................11
         5.14     Environmental Matters.................................................11
         5.15     Outstanding FNB Common Stock..........................................12
         5.16     Material Contracts....................................................12
         5.17     Employee Benefit Plans................................................12
         5.18     State Takeover Laws...................................................15
         5.19     Opinion of Financial Advisor..........................................15



                                       ii
   3

                                                                                     
ARTICLE 6 REPRESENTATIONS AND WARRANTIES OF FNB.........................................15
         6.1      Organization, Standing, and Power.....................................15
         6.2      Authority; No Breach By Agreement.....................................15
         6.3      Capital Stock.........................................................16
         6.4      FNB Subsidiaries......................................................16
         6.5      SEC Filings; Financial Statements.....................................17
         6.6      Absence of Certain Changes or Events..................................17
         6.7      Tax Matters...........................................................17
         6.8      Compliance With Laws..................................................18
         6.9      Assets................................................................19
         6.10     Legal Proceedings.....................................................19
         6.11     Reports...............................................................19
         6.12     Statements True and Correct...........................................19
         6.13     Accounting, Tax and Regulatory Matters................................20
         6.14     Environmental Matters.................................................20
         6.15     Outstanding Promistar Common Stock....................................21
         6.16     Material Contracts....................................................21
         6.17     Employee Benefit Plans................................................21
         6.18     Opinion of Financial Advisor.  FNB....................................23

ARTICLE 7 CONDUCT OF BUSINESS PENDING CONSUMMATION......................................24
         7.1      Mutual Covenants......................................................24
         7.2      Covenants of Promistar................................................25
         7.3      Covenants of FNB......................................................26
         7.4      Dividends.............................................................27
         7.5      Adverse Changes In Condition..........................................27
         7.6      Reports...............................................................27

ARTICLE 8 ADDITIONAL AGREEMENTS.........................................................28
         8.1      Registration Statement; Shareholder Approval..........................28
         8.2      Applications..........................................................28
         8.3      Filings With State Offices............................................28
         8.4      Agreement as to Efforts to Consummate.................................29
         8.5      Access to Information; Confidentiality................................29
         8.6      Press Releases........................................................30
         8.7      Current Information...................................................30
         8.8      Other Actions.........................................................31
         8.9      No Solicitation.......................................................31
         8.10     Accounting and Tax Treatment..........................................33
         8.11     Articles of Incorporation Provisions..................................33
         8.12     Agreement of Affiliates...............................................33
         8.13     Employment Contracts..................................................33
         8.14     Indemnification.......................................................34
         8.15     Additional Reports....................................................34
         8.16     Exemption from Liability under Section 16(b)..........................34
         8.17     Right to Update Disclosure Memoranda..................................35




                                      iii
   4

                                                                                     
ARTICLE 9 CONDITIONS PRECEDENT TO OBLIGATIONS TO
         CONSUMMATE.....................................................................35
         9.1      Conditions to Obligations of Each Party...............................35
         9.2      Conditions to Obligations of FNB......................................36
         9.3      Conditions to Obligations of Promistar................................37

ARTICLE 10 TERMINATION..................................................................38
         10.1     Termination...........................................................38
         10.2     Effect of Termination.................................................40
         10.3     Non-Survival of Representations and Covenants.........................40

ARTICLE 11 MISCELLANEOUS................................................................40
         11.1     Definitions...........................................................40
         11.2     Expenses..............................................................46
         11.3     Brokers and Finders...................................................47
         11.4     Entire Agreement......................................................47
         11.5     Amendments............................................................47
         11.6     Obligations of FNB....................................................47
         11.7     Waivers...............................................................47
         11.8     Assignment............................................................48
         11.9     Notices...............................................................48
         11.10    Governing Law.........................................................49
         11.11    Counterparts..........................................................49
         11.12    Captions..............................................................49
         11.13    Enforcement of Agreement..............................................49
         11.14    Severability..........................................................49




                                       iv
   5

                                LIST OF EXHIBITS



EXHIBIT
NUMBER   DESCRIPTION
- ------   -----------

      
   1     Form of Stock Option Agreement (Section 1.4)
   2     Form of agreement of affiliates of Promistar (Section 8.12)
   3     Form of outside directors' Non-Compete Agreement (Section 9.2(e))
   4     Form of opinion of Kirkpatrick & Lockhart LLP (Section 9.2(f))
   5     Form of opinion of Smith, Gambrell & Russell, LLP (Section 9.3(d))
   6     Entities Composing the Index Group (Section 10.1(g))



                                       v
   6

                          AGREEMENT AND PLAN OF MERGER

         THIS AGREEMENT AND PLAN OF MERGER (this "Agreement") is made and
entered into as of the 13th day of June, 2001, by and between F.N.B.
CORPORATION, a Florida corporation having its principal office located in
Naples, Florida ("FNB"), and PROMISTAR FINANCIAL CORPORATION, a Pennsylvania
corporation having its principal office located in Johnstown, Pennsylvania
("Promistar").

                                    PREAMBLE

         The Boards of Directors of Promistar and FNB believe that the
acquisition described herein is in the best interests of the parties and their
respective shareholders. This Agreement provides for the acquisition of
Promistar by FNB pursuant to the merger of Promistar with and into FNB (the
"Merger"). At the effective time of such Merger, the outstanding shares of the
capital stock of Promistar shall be converted into the right to receive shares
of the common stock of FNB (except as provided herein). As a result,
shareholders of Promistar shall become shareholders of FNB. Immediately upon
consummation of the Merger, Alpha Bank, a wholly owned subsidiary of Promistar,
shall be merged into First National Bank of Pennsylvania, a wholly owned
subsidiary of FNB. The transactions described in this Agreement are subject to
the approvals of the shareholders of Promistar and FNB, the Board of Governors
of the Federal Reserve System, the Office of the Comptroller of the Currency and
the Pennsylvania Department of Banking, and the satisfaction of certain other
conditions described in this Agreement. It is the intention of the parties to
this Agreement that the Merger for federal income tax purposes shall qualify as
a "reorganization" within the meaning of Section 368(a) of the Internal Revenue
Code, and for accounting purposes shall qualify for treatment as a pooling of
interests.

         Contemporaneously with the execution and delivery of this Agreement, as
a condition and inducement to FNB's willingness to enter into this Agreement,
Promistar and FNB are entering into a stock option agreement (the "Stock Option
Agreement"), in substantially the form attached hereto as Exhibit 1, pursuant to
which Promistar is granting to FNB an option to purchase shares of Promistar
Common Stock.

         Certain terms used in this Agreement are defined in Section 11.1 of
this Agreement.

         NOW, THEREFORE, in consideration of the above and the mutual
warranties, representations, covenants and agreements set forth herein, the
parties agree as follows:

                                   ARTICLE 1
                        TRANSACTIONS AND TERMS OF MERGER

         1.1      Merger. Subject to the terms and conditions of this Agreement,
at the Effective Time, Promistar shall be merged with and into FNB in accordance
with the provisions of the FBCA and the PBCL. At the Effective Time, the
separate existence of Promistar shall cease, and FNB shall be the Surviving
Corporation resulting from the Merger and shall continue to be governed by the
Laws of the State of Florida. From and after the Effective Time, the Merger
shall have the effects specified in the FBCA and the PBCL. The Merger shall be
consummated pursuant to the terms of this Agreement, which has been approved and
adopted by the respective Boards of Directors of Promistar and FNB.

         1.2      Time and Place of Closing. The closing of the transactions
contemplated by this Agreement (the "Closing"), including the Merger, shall take
place at 10:00 A.M., local time, on a date specified by the Parties as they,
acting through their chief executive officers or chief financial officers, may
mutually agree. Subject to the terms and conditions hereof, unless mutually
agreed upon in writing


                                       1
   7

by each Party, the Parties shall use their reasonable best efforts to cause the
Closing to occur on, but not prior to, the fifth business day following the
Approval Date.

         1.3      Effective Time. The Merger and other transactions contemplated
by this Agreement shall become effective upon (i) the later to occur of (A) the
date and time at which the Florida Articles of Merger containing the provisions
required by, and executed in accordance with, the FBCA shall have been accepted
for filing by the Florida Department of State, and (B) the date and time at
which the Pennsylvania Articles of Merger containing the provisions required by,
and executed in accordance with, the PBCL shall have been accepted for filing by
the Pennsylvania Department of State, or (ii) such later date and time as is
agreed in writing by FNB and Promistar and specified in the Florida Articles of
Merger and the Pennsylvania Articles of Merger (the time at which the Merger
becomes effective referred to herein as the "Effective Time"). Unless FNB and
Promistar otherwise mutually agree in writing, the Parties to this Agreement
shall use their best efforts to cause the Effective Time to occur on the date of
Closing.

         1.4      Execution of Stock Option Agreement. Concurrently with the
execution and delivery of this Agreement, and as a condition of FNB's
willingness to enter into this Agreement, Promistar is executing and delivering
to FNB the Stock Option Agreement.

                                    ARTICLE 2
                                 TERMS OF MERGER

         2.1      Articles of Incorporation. The Articles of Incorporation of
FNB in effect at the Effective Time shall be the Articles of Incorporation of
the Surviving Corporation until otherwise amended or repealed in accordance with
applicable Law.

         2.2      Bylaws. The Bylaws of FNB in effect at the Effective Time
shall be the Bylaws of the Surviving Corporation until otherwise amended or
repealed in accordance with applicable Law.

         2.3      FNB Board of Directors. Following the Effective Time, the
number of members of the FNB Board of Directors shall be increased by three
(which shall be accomplished by creating one vacancy in each of the three
classes of FNB directors) and three of the present members of the Board of
Directors of Promistar shall be elected by the FNB Board of Directors to fill
the vacancies so created. At the first annual meeting of the shareholders of FNB
following the Effective Time, the Board of Directors of FNB shall nominate for
reelection each of the directors elected pursuant to this Section 2.3. At the
third annual meeting following the Effective Time, the FNB Board of Directors
shall nominate for reelection the director elected pursuant to this Section 2.3
whose term expires at such meeting. At the fourth annual meeting following the
Effective Time, the FNB Board of Directors shall nominate for reelection the
director elected pursuant to this Section 2.3 whose term expires at such
meeting.

         2.4      First National Bank of Pennsylvania Board of Directors.
Following the Effective Time, FNB shall cause five of the directors of Promistar
or its Subsidiaries to be elected as members of the Board of Directors of First
National Bank of Pennsylvania.


                                       2
   8

                                    ARTICLE 3
                           MANNER OF CONVERTING SHARES

         3.1      Conversion of Shares. Subject to the provisions of this
Article 3, at the Effective Time, by virtue of the Merger and without any action
on the part of FNB, or Promistar, or the shareholders of either, the shares of
the constituent corporations shall be converted as follows:

         (a)      Each share of FNB Capital Stock issued and outstanding
immediately prior to the Effective Time shall remain issued and outstanding from
and after the Effective Time.

         (b)      Subject to Section 3.4 relating to fractional shares, each
share of Promistar Common Stock (excluding shares to be cancelled pursuant to
Section 3.3 of this Agreement) issued and outstanding at the Effective Time
shall cease to be outstanding and shall be converted into and exchanged for
0.926 shares of FNB Common Stock (subject to possible adjustment pursuant to
Section 10.1 hereof (the "Exchange Ratio").

         3.2      Anti-Dilution Provisions. In the event FNB changes the number
of shares of FNB Common Stock issued and outstanding prior to the Effective Time
as a result of a stock split, stock dividend, recapitalization, reclassification
or similar transaction with respect to such stock and the record date therefor
(in the case of a stock dividend) or the effective date thereof (in the case of
a stock split or similar recapitalization for which a record date is not
established) shall be prior to the Effective Time, the Exchange Ratio shall be
proportionately adjusted so as to prevent the dilutive effect of such
transaction on a percentage of ownership basis.

         3.3      Shares Held by Promistar or FNB. Each share of Promistar
Common Stock, if any, held by any Promistar Company or by any FNB Company, in
each case other than in a fiduciary capacity or as a result of debts previously
contracted, shall be canceled and retired at the Effective Time and no
consideration shall be issued in exchange therefor.

         3.4      Fractional Shares. Each shareholder of Promistar will have the
option of enrolling the shares of FNB Common Stock issued to such shareholder
pursuant to the Merger in FNB's Dividend Reinvestment and Stock Purchase Plan
(the "DRSP Plan"). Notwithstanding any other provision of this Agreement, each
holder of Promistar Common Stock exchanged pursuant to the Merger who elects not
to enroll in the DRSP Plan and who would otherwise have been entitled to receive
a fraction of a share of FNB Common Stock (after taking into account all
certificates delivered by such holder) shall receive, in lieu thereof, cash
(without interest) in an amount equal to such fractional part of a share of FNB
Common Stock multiplied by the "market price" of one share of FNB Common Stock
at the Closing. The market price of one share of FNB Common Stock at the Closing
shall be the closing price of such common stock, as reported by Nasdaq (or, if
not reported thereby, any other authoritative source selected by FNB) on the
last trading day preceding the Closing. No such holder will be entitled to
dividends, voting rights, or any other rights as a shareholder in respect of any
fractional shares. Each shareholder of Promistar electing to enroll in the DRSP
Plan will receive his or her share of FNB Common Stock issued pursuant to the
Merger in book-entry form, with any fractional share rounded to the third
decimal place, and such shareholder will be entitled to dividends and voting
rights with respect to such fractional share.

         3.5      Treatment of Options and Warrants.

         (a)      At the Effective Time, each option, warrant or other right to
purchase or acquire Promistar Common Stock (collectively, the "Promistar
Options") pursuant to stock awards, stock options, stock appreciation rights, or
other benefits granted by Promistar pursuant to any employee stock option plan
or other arrangement of Promistar ("Promistar Stock Plan"), which Promistar
Options are outstanding at the


                                       3
   9

Effective Time of the Merger, whether or not such Promistar Options are then
vested or exercisable, shall be converted into and become rights with respect to
FNB Common Stock, and FNB shall assume each Promistar Option, in accordance with
the terms of the Promistar Stock Plan, Stock Option agreement, or warrant
agreement by which it is evidenced, except that from and after the Effective
Time (i) FNB and its Compensation Committee shall be substituted for Promistar
and the compensation committee of Promistar's Board of Directors, including, if
applicable, the entire Board of Directors of Promistar, administering such
Promistar Stock Plan, (ii) each Promistar Option assumed by FNB may be exercised
solely for shares of FNB Common Stock, (iii) the number of shares of FNB Common
Stock subject to each such Promistar Option shall be equal to the number of
shares of Promistar Common Stock subject to each such Promistar Option
immediately prior to the Effective Time multiplied by the Exchange Ratio, and
(iv) the per share exercise price under each such Promistar Option will be
adjusted by dividing the per share exercise price under each such Promistar
Option by the Exchange Ratio and rounding up to the nearest cent.
Notwithstanding the provisions of clause (iii) of the preceding sentence, FNB
shall not be obligated to issue any fraction of a share of FNB Common Stock upon
exercise of Promistar Options and any fraction of a share of FNB Common Stock
that otherwise would be subject to a converted Promistar Option shall represent
the right to receive a cash payment equal to the product of such fraction and
the difference between the market value of one share of FNB Common Stock on the
date of exercise and the per share exercise price of such Option. Promistar and
FNB agree to take all necessary steps to effectuate the foregoing provisions of
this Section 3.5.

         (b)      As soon as practicable after the Effective Time, FNB shall
deliver to the participants in each Promistar Stock Plan an appropriate notice
setting forth such participant's rights pursuant thereto and the grants pursuant
to such Promistar Stock Plan shall continue in effect on the same terms and
conditions (subject to the adjustments required by Section 3.5(a) of this
Agreement after giving effect to the Merger), and FNB shall comply with the
terms of each Promistar Stock Plan to ensure, to the extent required by, and
subject to the provisions of, such Promistar Stock Plan, that Promistar Options
which qualified as incentive stock options prior to the Effective Time continue
to qualify as incentive stock options after the Effective Time. At or prior to
the Effective Time, FNB shall take all corporate action necessary to reserve for
issuance sufficient shares of FNB Common Stock for delivery upon exercise of
Promistar Options assumed by it in accordance with this Section 3.5. As soon as
practicable after the Effective Time, FNB shall file a registration statement on
Form S-3 or Form S-8, as the case may be (or any successor or other appropriate
forms), with respect to the shares of FNB Common Stock subject to such Promistar
Options and shall use its reasonable efforts to maintain the effectiveness of
such registration statement (and maintain the current status of the prospectus
or the prospectuses contained therein), for so long as such options remain
outstanding. With respect to individuals who subsequent to the Merger will be
subject to the reporting requirements under Section 16(a) of the 1934 Act, where
applicable, FNB shall administer the Promistar Stock Plan assumed pursuant to
this Section 3.5 in a manner which complies with Rule 16b-3 promulgated under
the 1934 Act to the extent the Promistar Stock Plan complied with such Rule
prior to the Merger.

         (c)      All restrictions or limitations on transfer with respect to
the Promistar Common Stock awarded under the Promistar Stock Plan or any other
plan, program, or arrangement of Promistar, to the extent that such restrictions
or limitations shall not have already lapsed, and except as otherwise expressly
provided in such plan, program, or arrangement, shall remain in full force and
effect.

                                   ARTICLE 4
                               EXCHANGE OF SHARES

         4.1      Exchange Procedures. At the Effective Time, FNB shall deposit,
or shall cause to be deposited, with First National Bank of Florida, a wholly
owned subsidiary of FNB (the "Exchange Agent") certificates evidencing shares of
FNB Common Stock and cash in such amounts necessary to


                                       4
   10

provide all consideration required to be exchanged by FNB for shares of
Promistar Common Stock pursuant to the terms of this Agreement. Promptly after
the Effective Time, FNB shall cause the Exchange Agent to mail to the former
shareholders of Promistar appropriate transmittal materials (which shall specify
that delivery shall be effected, and risk of loss and title to the certificates
theretofore representing shares of Promistar Common Stock shall pass, only upon
proper delivery of such certificates to the Exchange Agent). After the Effective
Time, each holder of shares of Promistar Common Stock (other than shares to be
canceled pursuant to Section 3.3 of this Agreement) issued and outstanding at
the Effective Time shall surrender the certificate or certificates representing
such shares to the Exchange Agent and shall upon surrender thereof promptly
receive in exchange therefor the consideration provided in Section 3.1 of this
Agreement, together with all declared but undelivered dividends or distributions
in respect of such shares (without interest thereon) pursuant to Section 4.2 of
this Agreement. To the extent required by Section 3.4 of this Agreement, each
holder of Promistar Common Stock issued and outstanding at the Effective Time
also shall receive, upon surrender of the certificate or certificates
representing such shares, cash in lieu of any fractional share of FNB Common
Stock to which such holder may be otherwise entitled (without interest). FNB
shall not be obligated to deliver the consideration to which any former holder
of Promistar Common Stock is entitled as a result of the Merger until such
holder surrenders such holder's certificate or certificates representing the
shares of Promistar Common Stock for exchange as provided in this Section 4.1.
The certificate or certificates of shares of Promistar Common Stock so
surrendered shall be duly endorsed as the Exchange Agent may require. Any other
provision of this Agreement notwithstanding, neither FNB nor the Exchange Agent
shall be liable to a holder of Promistar Common Stock for any amounts paid or
property delivered in good faith to a public official pursuant to any applicable
abandoned property Law. In the event any certificate representing shares of
Promistar Common Stock shall have been lost, stolen or destroyed, upon the
making of an affidavit of that fact by the person claiming such certificate to
be lost, stolen or destroyed, and, if required by FNB, the posting by such
person of a bond in such reasonable amount as FNB may direct as indemnity
against any claim that may be made against it with respect to such certificate,
FNB shall issue in exchange for such lost, stolen or destroyed certificate the
shares of FNB Common Stock deliverable in respect thereof determined in
accordance with this Agreement.

         4.2      Rights of Former Promistar Shareholders. The stock transfer
books of Promistar shall be closed as to holders of Promistar Common Stock
immediately prior to the Effective Time and no transfers of Promistar Common
Stock by any such holder shall thereafter be made or recognized. Until
surrendered for exchange in accordance with the provisions of Section 4.1 of
this Agreement, each certificate theretofore representing Promistar Common Stock
(other than shares to be canceled pursuant to Section 3.3 of this Agreement)
shall from and after the Effective Time represent for all purposes only the
right to receive the consideration provided in Sections 3.1 and 3.4 of this
Agreement in exchange therefor, subject, however, to FNB's obligation to pay any
dividends or make any other distributions with a record date prior to the
Effective Time which have been declared or made by Promistar in respect of such
Promistar Common Stock in accordance with the terms of this Agreement and which
remain unpaid at the Effective Time. Until 90 days after the Effective Time,
former shareholders of record of Promistar shall be entitled to vote at any
meeting of FNB stockholders the number of shares of FNB Common Stock into which
their respective shares of Promistar Common Stock are converted, regardless of
whether such holders have exchanged their certificates representing Promistar
Common Stock for certificates representing FNB Common Stock in accordance with
the provisions of this Agreement. Whenever a dividend or other distribution is
declared by FNB on the FNB Common Stock, the record date for which is at or
after the Effective Time, the declaration shall include dividends or other
distributions on all shares issuable pursuant to this Agreement, but beginning
30 days after the Effective Time no dividend or other distribution payable to
the holders of record of FNB Common Stock as of any time subsequent to the
Effective Time shall be delivered to the holder of any certificate representing
shares of Promistar Common Stock issued and outstanding at the Effective Time
until such holder surrenders such certificate for exchange as provided in
Section 4.1 of this Agreement. However, upon surrender of such Promistar


                                       5
   11

Common Stock certificate, both the FNB Common Stock certificate (together with
all such undelivered dividends or other distributions without interest) and any
undelivered dividends and cash payments to be paid for fractional share
interests (without interest) shall be delivered and paid with respect to each
share represented by such certificate. Any portion of the consideration
(including the proceeds of any investments thereof) which had been made
available to the Exchange Agent pursuant to Section 4.1 of this Agreement that
remains unclaimed by the shareholders of Promistar for 12 months after the
Effective Time shall be paid to FNB. Any shareholders of Promistar who have not
theretofore complied with this Article 4 shall thereafter look only to FNB
(subject to abandoned property, escheat or similar laws) and only as general
creditors thereof for payment of their shares of FNB Common Stock, cash in lieu
of fractional shares, and unpaid dividends and distributions on the FNB Common
Stock deliverable in respect of each Promistar Common Share such shareholder
holds as determined pursuant to this Agreement, in each case, without any
interest thereon.

                                    ARTICLE 5
                   REPRESENTATIONS AND WARRANTIES OF PROMISTAR

         Promistar hereby represents and warrants to FNB as follows:

         5.1      Organization, Standing, and Power. Promistar is a corporation
duly organized, validly existing, and in good standing under the laws of the
Commonwealth of Pennsylvania, and has the corporate power and authority to carry
on its business as now conducted and to own, lease and operate its material
Assets. Promistar is duly qualified or licensed to transact business as a
foreign corporation and is in good standing in each jurisdiction where the
character of its Assets or the nature or conduct of its business requires it to
be so qualified or licensed, except for such jurisdictions in which the failure
to be so qualified or licensed is not reasonably likely to have, individually or
in the aggregate, a Material Adverse Effect on Promistar.

         5.2      Authority; No Breach by Agreement.

         (a)      Promistar has the corporate power and authority necessary to
execute and deliver this Agreement and, subject to the approval and adoption of
this Agreement by the shareholders of Promistar, to perform its obligations
under this Agreement and consummate the transactions contemplated hereby. The
execution, delivery and performance of this Agreement by Promistar and the
consummation by Promistar of the transactions contemplated herein, including the
Merger, have been duly and validly authorized by all necessary corporate action
in respect thereof on the part of Promistar, subject to the approval of this
Agreement by its shareholders as contemplated by Section 8.1 of this Agreement.
Subject to such requisite shareholder approval (and assuming due authorization,
execution and delivery by FNB) and to such Consents of Regulatory Authorities as
required by applicable law, this Agreement represents a legal, valid and binding
obligation of Promistar, enforceable against Promistar in accordance with its
terms (except in all cases as such enforceability may be limited by applicable
bankruptcy, insolvency, reorganization, moratorium or similar Laws affecting the
enforcement of creditors' rights generally and except that the availability of
the equitable remedy of specific performance or injunctive relief is subject to
the discretion of the court before which any proceeding may be brought).

         (b)      Except as set forth in Section 5.2(b) of the Promistar
Disclosure Memorandum, neither the execution and delivery of this Agreement by
Promistar, nor the consummation by Promistar of the transactions contemplated
hereby, nor compliance by Promistar with any of the provisions hereof, will (i)
conflict with or result in a breach of any provision of Promistar's Articles of
Incorporation or Bylaws, or, (ii) constitute or result in a Default under, or
require any Consent pursuant to, or result in the creation of any Lien on any
Asset of any Promistar Company under, any Contract or Permit of any Promistar
Company, where such Default or Lien, or any failure to obtain such Consent, is
reasonably likely to have, individually or in the aggregate, a Material Adverse
Effect on Promistar, or (iii)


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subject to receipt of the requisite Consents referred to in Section 9.1(a), (b)
and (c) of this Agreement, violate any Order, or, to its Knowledge, any Law
applicable to any Promistar Company or any of their respective material Assets
which will have a Material Adverse Effect on Promistar.

         (c)      Other than in connection or compliance with the provisions of
the Securities Laws, applicable state corporate and securities Laws, and rules
of Nasdaq, and other than Consents required from Regulatory Authorities, and
other than notices to or filings with the Internal Revenue Service or the
Pension Benefit Guaranty Corporation with respect to any employee benefit plans,
or under the HSR Act, and other than Consents, filings, or notifications which,
if not obtained or made, are not reasonably likely to have, individually or in
the aggregate, a Material Adverse Effect on Promistar, no notice to, filing
with, or Consent of, any public body or authority is necessary for the
consummation by Promistar of the Merger and the other transactions contemplated
in this Agreement.

         5.3      Capital Stock.

         (a)      The authorized capital stock of Promistar consists of (i)
25,000,000 shares of Promistar Common Stock, of which 14,953,921 shares are
issued and outstanding as of the date of this Agreement, and (ii) 2,000,000
shares of preferred stock, no par value per share, none of which are outstanding
as of the date of this Agreement. All of the issued and outstanding shares of
capital stock of Promistar are duly and validly issued and outstanding and are
fully paid and nonassessable under the PBCL. None of the outstanding shares of
capital stock of Promistar has been issued in violation of any preemptive
rights. Promistar has reserved 1,260,000 shares of Promistar Common Stock for
issuance under the Promistar Stock Plans, pursuant to which, as of the date of
this Agreement, options and warrants to purchase not more than 748,500 shares of
Promistar Common Stock are outstanding.

         (b)      Except as set forth in Section 5.3(a) of this Agreement, as
provided pursuant to the Stock Option Agreement, or as set forth in Section
5.3(b) to the Promistar Disclosure Memorandum, there are no shares of capital
stock or other equity securities of Promistar outstanding and no outstanding
Rights relating to the capital stock of Promistar.

         5.4      Promistar Subsidiaries. Except as disclosed in Section 5.4 of
the Promistar Disclosure Memorandum, the list of Subsidiaries of Promistar filed
by Promistar as Exhibit 21.1 to its Annual Report on Form 10-K for the fiscal
year ended December 31, 2000, is a true and complete list of all of the
Promistar Subsidiaries as of the date of this Agreement. Except as disclosed in
Section 5.4 of the Promistar Disclosure Memorandum, Promistar or one of its
Subsidiaries owns all of the issued and outstanding shares of capital stock of
each Promistar Subsidiary. No equity securities of any Promistar Subsidiary are
or may become required to be issued (other than to another Promistar Company) by
reason of any Rights, and there are no Contracts by which any Promistar
Subsidiary is bound to issue (other than to another Promistar Company)
additional shares of its capital stock or Rights or by which any Promistar
Company is or may be bound to transfer any shares of the capital stock of any
Promistar Subsidiary (other than to another Promistar Company). There are no
Contracts relating to the rights of any Promistar Company to vote or to dispose
of any shares of the capital stock of any Promistar Subsidiary. All of the
shares of capital stock of each Promistar Subsidiary held by a Promistar Company
are fully paid and nonassessable under the applicable corporation Law of the
jurisdiction in which such Subsidiary is incorporated or organized (except, in
the case of Subsidiaries that are national banks, for the assessment
contemplated by 12 U.S.C. ss. 55), and are owned by such Promistar Company free
and clear of any Lien. Each Promistar Subsidiary is either a bank or a
corporation, and is duly organized, validly existing and (as to corporations) in
good standing under the Laws of the jurisdiction in which it is incorporated or
organized, and has the corporate power and authority necessary for it to own,
lease and operate its Assets and to carry on its business as now conducted. Each
Promistar Subsidiary is duly qualified or licensed to transact business as a
foreign corporation and is in good standing in each jurisdiction where the
character


                                       7
   13

of its Assets or the nature or conduct of its business requires it to be so
qualified or licensed, except for such jurisdictions in which the failure to be
so qualified or licensed is not reasonably likely to have, individually or in
the aggregate, a Material Adverse Effect on Promistar. Each Promistar Subsidiary
that is a depository institution is an "insured institution" as defined in the
Federal Deposit Insurance Act and applicable regulations thereunder.

         5.5      SEC Filings; Financial Statements.

         (a)      Promistar has filed and made available to FNB accurate and
complete copies of all forms, reports and documents required to be filed by
Promistar with the SEC since January 1, 1996 (collectively, the "Promistar SEC
Reports"). The Promistar SEC Reports (i) at the time filed, complied in all
material respects with the applicable requirements of the 1933 Act and the 1934
Act, as the case may be, and (ii) did not at the time they were filed (or if
amended or superseded by a filing prior to the date of this Agreement, then on
the date of such filing) contain any untrue statement of a material fact or omit
to state a material fact required to be stated in such Promistar SEC Reports or
necessary in order to make the statements in such Promistar SEC Reports, in
light of the circumstances under which they were made, not misleading. Except
for Promistar Subsidiaries that are registered as brokers, dealers, investment
advisers or associated persons thereof, none of the Promistar Subsidiaries is
required to file any forms, reports or other documents with the SEC.

         (b)      Each of the Promistar Financial Statements (including, in each
case, any related notes) contained in the Promistar SEC Reports, including any
Promistar SEC Reports filed after the date of this Agreement until the Effective
Time, complied, and each Promistar SEC Report filed after the date of this
Agreement until the Effective Time will comply, as to form in all material
respects with the applicable published rules and regulations of the SEC with
respect thereto, was or will be prepared in accordance with GAAP applied on a
consistent basis throughout the periods involved (except as may be indicated in
the notes to such financial statements or, in the case of unaudited statements,
as permitted by Form 10-Q of the SEC), and fairly presented the consolidated
financial position of Promistar and its Subsidiaries at the respective dates and
the consolidated results of its operations and cash flows for the periods
indicated, except that the unaudited interim financial statements were or are
subject to normal and recurring adjustments which were not or are not expected
to be material in amount.

         5.6      Absence of Certain Changes or Events. Since March 31, 2001,
(i) there have been no events, changes or occurrences which have had, or are
reasonably likely to have, individually or in the aggregate, a Material Adverse
Effect on Promistar, and (ii) the Promistar Companies have not taken any action,
or failed to take any action, prior to the date of this Agreement, which action
or failure, if taken after the date of this Agreement, would represent or result
in a material breach or violation of any of the covenants and agreements of
Promistar provided in Articles 7 or 8 of this Agreement.

         5.7      Tax Matters.

         (a)      All Tax Returns required to be filed by or on behalf of any of
the Promistar Companies have been timely filed or requests for extensions have
been timely filed, granted, and have not expired for periods ended on or before
December 31, 2000, and on or before the date of the most recent fiscal year end
immediately preceding the Effective Time, except to the extent that all such
failures to file, taken together, are not reasonably likely to have a Material
Adverse Effect on Promistar, and all Tax Returns filed are complete and accurate
in all material respects. All Taxes shown on filed Tax Returns have been paid.
There is no audit examination, deficiency, or refund Litigation with respect to
any Taxes that is reasonably likely to result in a determination that would
have, individually or in the aggregate, a Material Adverse Effect on Promistar,
except as reserved against in the Promistar Financial Statements delivered


                                       8
   14

prior to the date of this Agreement. All Taxes and other liabilities due with
respect to completed and settled examinations or concluded Litigation have been
paid.

         (b)      Adequate provision for any Taxes due or, to the Knowledge of
Promistar, to become due for any of the Promistar Companies for the period or
periods through and including the date of the respective Promistar Financial
Statements has been made and is reflected on such Promistar Financial
Statements.

         (c)      Deferred Taxes of the Promistar Companies have been adequately
provided for in the Promistar Financial Statements.

         (d)      To the Knowledge of Promistar, each of the Promistar Companies
is in compliance with, and its records contain all information and documents
(including properly completed Internal Revenue Service Forms W-9) necessary to
comply with, all applicable information reporting and Tax withholding
requirements under federal, state and local Tax Laws, and such records identify
with specificity all accounts subject to backup withholding under Section 3406
of the Internal Revenue Code, except for such instances of noncompliance and
such omissions as are not reasonably likely to have, individually or in the
aggregate, a Material Adverse Effect on Promistar.

         5.8      Compliance With Laws. Promistar is duly registered as a bank
holding company under the BHC Act. Each Promistar Company has in effect all
Permits necessary for it to own, lease, or operate its material Assets and to
carry on its business as now conducted, except for those Permits the absence of
which are not reasonably likely to have, individually or in the aggregate, a
Material Adverse Effect on Promistar. None of the Promistar Companies is
presently in Default under or in violation of any such Permit, other than
Defaults which are not reasonably likely to have, individually or in the
aggregate, a Material Adverse Effect on Promistar. Except as set forth in
Section 5.8 of the Promistar Disclosure Memorandum, no Promistar Company:

         (i)      is in violation of any Laws, Orders, or Permits applicable to
its business or employees conducting its business, except for violations which
are not reasonably likely to have, individually or in the aggregate, a Material
Adverse Effect on Promistar; or

         (ii)     has received any notification or communication from any agency
or department of federal, state, or local government or any Regulatory Authority
or the staff thereof (i) asserting that any Promistar Company is not in
compliance with any of the Laws or Orders which such governmental authority or
Regulatory Authority enforces, where such noncompliance is reasonably likely to
have, individually or in the aggregate, a Material Adverse Effect on Promistar,
(ii) threatening to revoke any Permits, the revocation of which is reasonably
likely to have, individually or in the aggregate, a Material Adverse Effect on
Promistar, or (iii) requiring any Promistar Company to enter into or consent to
the issuance of a cease and desist order, formal agreement, directive,
commitment, or memorandum of understanding, or to adopt any board resolution or
similar undertaking, which restricts materially the conduct of its business, or
in any manner relates to its capital adequacy, its credit or reserve policies,
its management or the payment of dividends.

         5.9      Assets. Except as disclosed in Section 5.9 of the Promistar
Disclosure Memorandum, the Promistar Companies have good and marketable title,
free and clear of all Liens (except for those Liens which are not likely to have
a Material Adverse Effect on Promistar or its Subsidiaries taken as a whole), to
all of their respective Assets. All material tangible properties used in the
businesses of the Promistar Companies are in good condition, reasonable wear and
tear excepted, and are usable in the ordinary course of business consistent with
Promistar's past practices. All Assets which are material to Promistar's
business on a consolidated basis, held under leases or subleases by any of the
Promistar


                                       9
   15

Companies, are held under valid Contracts enforceable in accordance with their
respective terms (except as enforceability may be limited by applicable
bankruptcy, insolvency, reorganization, moratorium, or other Laws affecting the
enforcement of creditors' rights generally and except that the availability of
the equitable remedy of specific performance or injunctive relief is subject to
the discretion of the court before which any proceedings may be brought), and
each such Contract is in full force and effect. The Promistar Companies
currently maintain insurance in amounts, scope, and coverage as disclosed in
Section 5.9 of the Promistar Disclosure Memorandum. None of the Promistar
Companies has received written notice from any insurance carrier that (i) such
insurance will be canceled or that coverage thereunder will be reduced or
eliminated, or (ii) premium costs with respect to such policies of insurance
will be substantially increased. Except as disclosed in Section 5.9 of the
Promistar Disclosure Memorandum, to the Knowledge of Promistar there are
presently no occurrences giving rise to a claim under such policies of insurance
and no notices have been given by any Promistar Company under such policies.

         5.10     Legal Proceedings. There is no Litigation instituted or
pending, or, to the Knowledge of Promistar, threatened against any Promistar
Company, or against any Asset, employee benefit plan, interest, or right of any
of them, that is reasonably likely to have, individually or in the aggregate, a
Material Adverse Effect on Promistar, nor are there any Orders of any Regulatory
Authorities, other governmental authorities, or arbitrators outstanding against
any Promistar Company, that are reasonably likely to have, individually or in
the aggregate, a Material Adverse Effect on Promistar.

         5.11     Reports. Since January 1, 1996, or the date of organization if
later, each Promistar Company has filed all reports and statements, together
with any amendments required to be made with respect thereto, that it was
required to file with Regulatory Authorities (except, in the case of state
securities authorities, failures to file which are not reasonably likely to
have, individually or in the aggregate, a Material Adverse Effect on Promistar).
As of its respective date, each such report and document, including the
financial statements, exhibits, and schedules thereto, (i) complied in all
material respects with all applicable Laws, and (ii) did not, in all material
respects, contain any untrue statement of a material fact or omit to state a
material fact required to be stated therein or necessary to make the statements
made therein, in light of the circumstances under which they were made, not
misleading, which untrue statement of material fact or omission to state a
material fact is likely to have, individually, or in the aggregate, a Material
Adverse Effect on Promistar.

         5.12     Statements True and Correct. None of the information supplied
or to be supplied by any Promistar Company or any Affiliate thereof for
inclusion in the Registration Statement will, when the Registration Statement
becomes effective, be false or misleading with respect to any material fact, or
omit to state any material fact necessary to make the statements therein not
misleading. None of the information supplied or to be supplied by any Promistar
Company or any Affiliate thereof for inclusion in the Joint Proxy Statement or
any other documents to be filed by Promistar or FNB with the SEC or any other
Regulatory Authority in connection with the transactions contemplated hereby
will, at the respective time such documents are filed, and with respect to the
Joint Proxy Statement, when first mailed to the shareholders of FNB or
Promistar, be false or misleading with respect to any material fact, or omit to
state any material fact necessary to make the statements therein, in light of
the circumstances under which they were made, not misleading, or, in the case of
the Joint Proxy Statement or any amendment thereof or supplement thereto, at the
time of the FNB Shareholders' Meeting or the Promistar Shareholders' Meeting, be
false or misleading with respect to any material fact, or omit to state any
material fact necessary to correct any statement in any earlier communication
with respect to the solicitation of any proxy for the FNB Shareholders' Meeting
or the Promistar Shareholders' Meeting. All documents that any Promistar Company
or any Affiliate thereof is responsible for filing with any Regulatory Authority
in connection with the transactions contemplated hereby will comply as to form
in all material respects with the provisions of applicable Law.


                                       10
   16

         5.13     Accounting, Tax and Regulatory Matters. No Promistar Company
or any Affiliate thereof has taken or agreed to take any action or has any
Knowledge of any fact or circumstance that is reasonably likely to (i) prevent
the transactions contemplated hereby, including the Merger, from qualifying for
pooling-of-interests accounting treatment or as a reorganization within the
meaning of Section 368(a)(2)(D) of the Internal Revenue Code, or (ii) materially
impede or delay receipt of any Consents of Regulatory Authorities referred to in
Section 9.1(b) of this Agreement or result in the imposition of a condition or
restriction of the type referred to in the last sentence of such Section.

         5.14     Environmental Matters.

         (a)      To the Knowledge of Promistar, except as disclosed in Section
5.14 of the Promistar Disclosure Memorandum, each Promistar Company, its
Participation Facilities, and its Loan Properties are, and have been, in
compliance with all Environmental Laws, except for violations which are not
reasonably likely to have, individually or in the aggregate, a Material Adverse
Effect on Promistar.

         (b)      Except as disclosed in Section 5.14 of the Promistar
Disclosure Memorandum, there is no Litigation pending, or, to the Knowledge of
Promistar, threatened before any court, governmental agency, or authority or
other forum in which any Promistar Company or any of its Loan Properties or
Participation Facilities (or any Promistar Company in respect of any such Loan
Property or Participation Facility) has been or, with respect to threatened
Litigation, may be named as a defendant or potentially responsible party (i) for
alleged noncompliance (including by any predecessor) with any Environmental Law
or (ii) relating to the release into the environment of any Hazardous Material,
whether or not occurring at, on, under, or involving any of its Loan Properties
or Participation Facilities, except for such Litigation pending or threatened
that is not reasonably likely to have, individually or in the aggregate, a
Material Adverse Effect on Promistar.

         (c)      To the Knowledge of Promistar, except as disclosed in Section
5.14 of the Promistar Disclosure Memorandum, there is no reasonable basis for
any Litigation of a type described above in Section 5.14(b), except such as is
not reasonably likely to have, individually or in the aggregate, a Material
Adverse Effect on Promistar.

         (d)      To the Knowledge of Promistar, except as disclosed in Section
5.14 of the Promistar Disclosure Memorandum, during the period of (i)
Promistar's or any of its Subsidiaries' ownership or operation of any of their
respective properties, (ii) Promistar's or any of its Subsidiaries'
participation in the management of any Participation Facility, or (iii)
Promistar's or any of its Subsidiaries' holding a security interest in a Loan
Property, there has been no release of Hazardous Material in, on, under, or
affecting any Participation Facility or Loan Property of a Promistar Company,
except such as are not reasonably likely to have, individually or in the
aggregate, a Material Adverse Effect on Promistar.

         5.15     Outstanding FNB Common Stock. As of the date of this
Agreement, Promistar Companies do not beneficially own any shares of FNB Common
Stock for their own accounts (not including those held in a fiduciary or trust
capacity for, or on behalf of, unaffiliated third parties). During the term of
this Agreement, no Promistar Company shall purchase or otherwise acquire
beneficial ownership of any FNB Common Stock except pursuant to the terms of
this Agreement.

         5.16     Material Contracts. Except as set forth in the Promistar SEC
Reports or in Section 5.16 of the Promistar Disclosure Memorandum, no Promistar
Company is a party to or bound by any "material contract" as such term is
defined in Item 601(b)(10) of Regulation S-K of the SEC (each such contract a
"Promistar Contract"). With respect to each Promistar Contract and except as
disclosed in Section 5.16 of the Promistar Disclosure Memorandum: (i) such
Promistar Contract is in full force and effect; (ii) no Promistar Company is in
Default thereunder; (iii) no


                                       11
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Promistar Company has repudiated or waived any material provision of any such
Promistar Contract; and (iv) no other party to any such Contract is, to the
Knowledge of Promistar, in Default in any respect or has repudiated or waived
any material provision thereunder.

         5.17     Employee Benefit Plans.

         (a)      Promistar has disclosed in Section 5.17 of the Promistar
Disclosure Memorandum, and has delivered or made available to FNB prior to the
execution of this Agreement copies in each case of: (i) all pension, retirement,
profit-sharing, deferred compensation, stock option, employee stock ownership,
severance pay, vacation, bonus, or other incentive plan, all other written
employee programs, arrangements, or agreements, all medical, vision, dental, or
other health plans, all life insurance plans, and all other employee benefit
plans or fringe benefit plans, including, without limitation, "employee benefit
plans" (as that term is defined in Section 3(3) of ERISA), currently adopted,
maintained by, sponsored in whole or in part by, or contributed to by any
Promistar Company or ERISA Affiliate (as defined below) thereof for the benefit
of employees, retirees, dependents, spouses, directors, independent contractors,
or other beneficiaries and under which employees, retirees, dependents, spouses,
directors, independent contractors, or other beneficiaries are eligible to
participate (collectively, the "Promistar Benefit Plans"); (ii) all insurance
contracts, annuity contracts and other funding vehicles relating to the
Promistar Benefit Plans; (iii) all material agreements entered into with service
providers in connection with the Promistar Benefit Plans; and (iv) summary plan
descriptions, favorable Internal Revenue Service determination letters for each
Promistar ERISA Plan intended to be qualified under Section 401(a) of the
Internal Revenue Code and the most recently available Form 5500 annual reports,
certified financial statement and actuarial reports for the Promistar Benefit
Plans. Any of the Promistar Benefit Plans which is an "employee pension benefit
plan" (as that term is defined in Section 3(2) of ERISA), is referred to herein
as a "Promistar ERISA Plan." Each Promistar ERISA Plan which is also a "defined
benefit plan" (as defined in Section 4140 of the Internal Revenue Code) is
referred to herein as a "Promistar Pension Plan." No Promistar Pension Plan is
or has been a multiemployer plan within the meaning of Section 3(37) of ERISA.
No Promistar Benefit Plan is a multiple employer plan within the meaning of
Section 413(c) of the Internal Revenue Code or is a multiple employer welfare
arrangement within the meaning of Section 3(40) of ERISA. Since the date the
foregoing documents were delivered or made available to FNB, no amendments to
any Promistar Benefit Plan have been made or will be made prior to the Closing
Date. Except as disclosed in Section 5.17 of the Promistar Disclosure
Memorandum, Promistar does not maintain any unwritten Promistar Benefit Plans.
No Promistar Company nor any ERISA Affiliate is a party to a collective
bargaining agreement. Promistar has disclosed in Section 5.17 of the Promistar
Disclosure Memorandum a complete and accurate list of (A) each ERISA Affiliate,
and (B) each Promistar ERISA Plan that has not been adopted by each ERISA
Affiliate that maintains a separate payroll.

         (b)      Except as disclosed in Section 5.17 of the Promistar
Disclosure Memorandum, all Promistar Benefit Plans are in compliance with the
applicable terms of ERISA, the Internal Revenue Code, COBRA (as defined below)
and any other applicable Laws the breach or violation of which are reasonably
likely to have, individually or in the aggregate, a Material Adverse Effect on
Promistar, and each Promistar ERISA Plan which is intended to be qualified under
Section 401(a) of the Internal Revenue Code has received a favorable
determination letter from the Internal Revenue Service, and Promistar is not
aware of any circumstances likely to result in revocation of any such favorable
determination letter. Except as disclosed in Section 5.17 of the Promistar
Disclosure Memorandum, to the Knowledge of Promistar, no Promistar Company nor
any ERISA Affiliate has any liability to the Internal Revenue Service with
respect to any Promistar Benefit Plan, including any liability imposed by
Chapter 43 of the Internal Revenue Code, and no Promistar Company has engaged in
a transaction with respect to any Promistar Benefit Plan that, assuming the
taxable period of such transaction expired as of the date hereof, would subject
any Promistar Company to a Tax imposed by either Section 4975 of the Internal


                                       12
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Revenue Code or Section 502(i) of ERISA in amounts which are reasonably likely
to have, individually or in the aggregate, a Material Adverse Effect on
Promistar.

         (c)      Except as disclosed in Section 5.17 of the Promistar
Disclosure Memorandum, no Promistar Pension Plan has any "unfunded current
liability" (as that term is defined in Section 302(d)(8)(A) of ERISA) and the
fair market value of the assets of any such plan exceeds the plan's "benefit
liabilities," as that term is defined in Section 4001(a)(16) of ERISA, when
determined under actuarial factors that would apply if the plan terminated in
accordance with all applicable legal requirements. Except as disclosed in
Section 5.17 of the Promistar Disclosure Memorandum, since the date of the most
recent actuarial valuation, there has been (i) no material change in the
financial position of any Promistar Pension Plan, (ii) no change in the
actuarial assumptions with respect to any Promistar Pension Plan, and (iii) no
increase in benefits under any Promistar Pension Plan as a result of plan
amendments or changes in applicable Law which is reasonably likely to have,
individually or in the aggregate, a Material Adverse Effect on Promistar or
materially adversely affect the funding status of any such plan. Neither any
Promistar Pension Plan nor any "single-employer plan," within the meaning of
Section 4001(a)(15) of ERISA, currently or formerly maintained by any Promistar
Company, or the single-employer plan of any entity which is considered one
employer with Promistar under Section 4001 of ERISA or Section 414 of the
Internal Revenue Code or Section 302 of ERISA (whether or not waived) (an "ERISA
Affiliate") has an "accumulated funding deficiency" within the meaning of
Section 412 of the Internal Revenue Code or Section 302 of ERISA, which is
reasonably likely to have a Material Adverse Effect on Promistar. No Promistar
Company has provided, or is required to provide, security to a Promistar Pension
Plan or to any single-employer plan of an ERISA Affiliate pursuant to Section
401(a)(29) of the Internal Revenue Code.

         (d)      Within the six-year period preceding the Effective Time, no
liability under Subtitle C or D of Title IV of ERISA has been or is expected to
be incurred by any Promistar Company with respect to any ongoing, frozen, or
terminated single-employer plan or the single-employer plan of any ERISA
Affiliate, which liability is reasonably likely to have a Material Adverse
Effect on Promistar. No Promistar Company has incurred any withdrawal liability
with respect to a multiemployer plan under Subtitle B of Title IV of ERISA
(regardless of whether based on contributions of an ERISA Affiliate), which
liability is reasonably likely to have a Material Adverse Effect on Promistar.
No notice of a "reportable event," within the meaning of Section 4043 of ERISA
for which the 30-day reporting requirement has not been waived, has been
required to be filed for any Promistar Pension Plan or by any ERISA Affiliate
within the 12-month period ending on the date hereof. No Promistar Company nor
ERISA Affiliate has filed a notice of intent to terminate any ERISA Pension Plan
or has adopted any amendment to treat such Plan as terminated. The Pension
Benefit Guaranty Corporation has not instituted proceedings to treat any ERISA
Pension Plan as terminated. No event has occurred or circumstance exists that
may constitute grounds under Section 4042 of ERISA for the termination of, or
appointment of a trustee to administer, any Promistar Pension Plan.

         (e)      Except as disclosed in Section 5.17 of the Promistar
Disclosure Memorandum, no Promistar Company has any liability for retiree health
and life benefits under any of the Promistar Benefit Plans other than health
continuation coverage required by the Consolidated Omnibus Budget Reconciliation
Act of 1985 as amended and Sections 601 through 608 of ERISA ("COBRA") or by any
similar state law, and there are no restrictions on the rights of such Promistar
Company to amend or terminate any such plan without incurring any liability
thereunder, which liability is reasonably likely to have a Material Adverse
Effect on Promistar. There is no pending or, to the Knowledge of Promistar,
threatened complaint, claim (other than a routine claim for benefits submitted
by participants or beneficiaries), proceeding, audit or investigation of any
kind in or before any court, tribunal, or governmental agency with respect to
any Promistar Benefit Plan.


                                       13
   19

         (f)      Except as disclosed in Section 5.17 of the Promistar
Disclosure Memorandum, neither the execution and delivery of this Agreement nor
the consummation of the transactions contemplated hereby will (i) result in any
payment (including severance, unemployment compensation, golden parachute, or
otherwise) becoming due to any director or any employee of any Promistar Company
from any Promistar Company under any Promistar Benefit Plan or otherwise, (ii)
increase any benefits otherwise payable under any Promistar Benefit Plan, or
(iii) result in any acceleration of the time of payment or vesting of any such
benefit, where such payment, increase, or acceleration is reasonably likely to
have, individually or in the aggregate, a Material Adverse Effect on Promistar.

         (g)      The actuarial present values of all accrued deferred
compensation entitlements (including entitlements under any executive
compensation, supplemental retirement, or employment agreement) of employees and
former employees of any Promistar Company and their respective beneficiaries,
other than entitlements accrued pursuant to funded retirement plans subject to
the provisions of Section 412 of the Internal Revenue Code or Section 302 of
ERISA, have been fully reflected on the Promistar Financial Statements to the
extent required by and in accordance with GAAP.

         (h)      Except as disclosed in Section 5.17(h) of the Promistar
Disclosure Memorandum, all contributions and payments made or accrued with
respect to all Promistar Benefit Plans are deductible under Sections 404 or 162
of the Internal Revenue Code and, if not made, are properly reflected on the
financial statements of the Promistar Companies and ERISA Affiliates. No event
has occurred or circumstance exists that could result in an increase in premium
costs of insured or self-insured Promistar Benefit Plans that would have a
Material Adverse Effect on Promistar. Levels of insurance reserves, trust
funding and accrued liabilities with respect to all ERISA Benefit Plans (to
which such reserves or liabilities do or should apply) are reasonable and
sufficient to provide for all incurred but unreported claims and any retroactive
or prospective premium adjustments.

         5.18     State Takeover Laws. Promistar has taken all action required
to be taken by it in order to exempt this Agreement and the Stock Option
Agreement and the transactions contemplated hereby and thereby from, and the
Agreement and the Stock Option Agreement and the transactions contemplated
hereby and thereby are exempt from the requirements of any "moratorium,"
"control share," "fair price" or other anti-takeover Laws of the Commonwealth of
Pennsylvania.

         5.19     Opinion of Financial Advisor. Promistar has received the
written opinion of Keefe, Bruyette and Woods, Inc., its financial advisor, to
the effect that, as of the date hereof, the consideration to be received by the
Promistar shareholders, based upon and subject to the limitations set forth in
such opinion, is fair to the Promistar shareholders from a financial point of
view.

                                    ARTICLE 6
                      REPRESENTATIONS AND WARRANTIES OF FNB

         FNB hereby represents and warrants to Promistar as follows:

         6.1      Organization, Standing, and Power. FNB is a corporation duly
organized, validly existing, and in active status under the laws of the State of
Florida, and has the corporate power and authority to carry on its business as
now conducted and to own, lease and operate its material Assets. FNB is duly
qualified or licensed to transact business as a foreign corporation and is in
good standing in each jurisdiction where the character of its Assets or the
nature or conduct of its business requires it to be so qualified or licensed,
except for such jurisdictions in which the failure to be so qualified or
licensed is not reasonably likely to have, individually or in the aggregate, a
Material Adverse Effect on FNB.


                                       14
   20

         6.2      Authority; No Breach By Agreement.

         (a)      FNB has the corporate power and authority necessary to execute
and deliver this Agreement and, subject to the approval and adoption of this
Agreement by the shareholders of FNB and to such Consents of Regulatory
Authorities as required under applicable law, to perform its obligations under
this Agreement and consummate the transactions contemplated hereby. The
execution, delivery, and performance of this Agreement by FNB and the
consummation by FNB of the transactions contemplated herein, including the
Merger, have been duly and validly authorized by all necessary corporate action
in respect thereof on the part of FNB, subject to the approval of this Agreement
by its shareholders as contemplated by Section 8.1 of this Agreement. Subject to
such requisite shareholder approval (and assuming due authorization, execution
and delivery by Promistar) and to such Consents of Regulatory Authorities as
required by applicable law, this Agreement represents a legal, valid, and
binding obligation of FNB, enforceable against FNB in accordance with its terms
(except in all cases as such enforceability may be limited by applicable
bankruptcy, insolvency, reorganization, moratorium or similar Laws affecting the
enforcement of creditors' rights generally and except that the availability of
the equitable remedy of specific performance or injunctive relief is subject to
the discretion of the court before which any proceeding may be brought).

         (b)      Neither the execution and delivery of this Agreement by FNB,
nor the consummation by FNB of the transactions contemplated hereby, nor
compliance by FNB with any of the provisions hereof, will (i) conflict with or
result in a breach of any provision of FNB's Articles of Incorporation or
Bylaws, or, (ii) constitute or result in a Default under, or require any Consent
pursuant to, or result in the creation of any Lien on any Asset of any FNB
Company under, any Contract or Permit of any FNB Company, where such Default or
Lien, or any failure to obtain such Consent, is reasonably likely to have,
individually or in the aggregate, a Material Adverse Effect on FNB, or, (iii)
subject to receipt of the requisite Consents referred to in Section 9.1(a), (b)
and (c) of this Agreement, violate any Order, or to its Knowledge, any Law
applicable to any FNB Company or any of their respective material Assets which
will have a Material Adverse Effect on FNB.

         (c)      Other than in connection or compliance with the provisions of
the Securities Laws, applicable state corporate and securities Laws, and rules
of Nasdaq, and other than Consents required from Regulatory Authorities, and
other than notices to or filings with the Internal Revenue Service or the
Pension Benefit Guaranty Corporation with respect to any employee benefit plans,
or under the HSR Act, and other than Consents, filings, or notifications which,
if not obtained or made, are not reasonably likely to have, individually or in
the aggregate, a Material Adverse Effect on FNB, no notice to, filing with, or
Consent of, any public body or authority is necessary for the consummation by
FNB of the Merger and the other transactions contemplated in this Agreement.

         6.3      Capital Stock. The authorized capital stock of FNB consists of
(i) 100,000,000 shares of FNB Common Stock, of which 25,556,384 shares were
issued and outstanding as of the date of this Agreement and (ii) 20,000,000
shares of FNB Preferred Stock, of which 163,667 shares were issued and
outstanding as of the date of this Agreement ("FNB Capital Stock"). All of the
issued and outstanding shares of FNB Capital Stock are, and all of the FNB
Common Stock to be issued in exchange for Promistar Common Stock upon
consummation of the Merger will be authorized and reserved for issuance prior to
the Effective Time and, when issued in accordance with the terms of this
Agreement, will be, duly and validly issued and outstanding and fully paid and
nonassessable under the FBCA. None of the outstanding shares of FNB Capital
Stock has been, and none of the shares of FNB Common Stock to be issued in
exchange for shares of Promistar Common Stock upon consummation of the Merger
will be, issued in violation of any preemptive rights of the current or past
shareholders of FNB.


                                       15
   21

         6.4      FNB Subsidiaries. Except as disclosed in Section 6.4 of the
FNB Disclosure Memorandum, the list of Subsidiaries of FNB filed by FNB with its
Annual Report on Form 10-K for the fiscal year ended December 31, 2000, is a
true and complete list of all of the FNB Subsidiaries as of the date of this
Agreement. Except as disclosed in Section 6.4 of the FNB Disclosure Memorandum,
FNB or one of its Subsidiaries owns all of the issued and outstanding shares of
capital stock of each FNB Subsidiary. No equity securities of any FNB Subsidiary
are or may become required to be issued (other than to another FNB Company) by
reason of any Rights, and there are no Contracts by which any FNB Subsidiary is
bound to issue (other than to another FNB Company) additional shares of its
capital stock or Rights or by which any FNB Company is or may be bound to
transfer any shares of the capital stock of any FNB Subsidiary (other than to
another FNB Company). There are no Contracts relating to the rights of any FNB
Company to vote or to dispose of any shares of the capital stock of any FNB
Subsidiary. All of the shares of capital stock of each FNB Subsidiary held by a
FNB Company are fully paid and nonassessable under the applicable corporation
Law of the jurisdiction in which such Subsidiary is incorporated or organized
(except, in the case of Subsidiaries that are national banks, for the assessment
contemplated by 12 U.S.C. ss. 55), and are owned by the FNB Company free and
clear of any Lien. Each FNB Subsidiary is either a bank, a corporation or a
limited liability company, and is duly organized, validly existing, and (as to
corporations) in good standing under the Laws of the jurisdiction in which it is
incorporated or organized, and has the corporate power and authority necessary
for it to own, lease, and operate its Assets and to carry on its business as now
conducted. Each FNB Subsidiary is duly qualified or licensed to transact
business as a foreign corporation and is in good standing in each jurisdiction
where the character of its Assets or the nature or conduct of its business
requires it to be so qualified or licensed, except for such jurisdictions in
which the failure to be so qualified or licensed is not reasonably likely to
have, individually or in the aggregate, a Material Adverse Effect on FNB. Each
FNB Subsidiary that is a depository institution is an "insured institution" as
defined in the Federal Deposit Insurance Act and applicable regulations
thereunder.

         6.5      SEC Filings; Financial Statements.

         (a)      FNB has filed and made available to Promistar accurate and
complete copies of all forms, reports, and documents required to be filed by FNB
with the SEC since January 1, 1996 (collectively, the "FNB SEC Reports"). The
FNB SEC Reports (i) at the time filed, complied in all material respects with
the applicable requirements of the 1933 Act and the 1934 Act, as the case may
be, and (ii) did not at the time they were filed (or if amended or superseded by
a filing prior to the date of this Agreement, then on the date of such filing)
contain any untrue statement of a material fact or omit to state a material fact
required to be stated in such FNB SEC Reports or necessary in order to make the
statements in such FNB SEC Reports, in light of the circumstances under which
they were made, not misleading. Except for FNB Subsidiaries that are registered
as brokers, dealers, investment advisers, or associated persons thereof, none of
the FNB Subsidiaries is required to file any forms, reports or other documents
with the SEC.

         (b)      Each of the FNB Financial Statements (including, in each case,
any related notes) contained in the FNB SEC Reports, including any FNB SEC
Reports filed after the date of this Agreement until the Effective Time,
complied, and each FNB SEC Report filed after the date of this Agreement until
the Effective Time will comply, as to form in all material respects with the
applicable published rules and regulations of the SEC with respect thereto, was
or will be prepared in accordance with GAAP applied on a consistent basis
throughout the periods involved (except as may be indicated in the notes to such
financial statements or, in the case of unaudited statements, as permitted by
Form 10-Q of the SEC), and fairly presented the consolidated financial position
of FNB and its Subsidiaries at the respective dates and the consolidated results
of its operations and cash flows for the periods indicated, except that the
unaudited interim financial statements were or are subject to normal and
recurring adjustments which were not or are not expected to be material in
amount.


                                       16
   22

         6.6      Absence of Certain Changes or Events. Since March 31, 2001,
(i) there have been no events, changes, or occurrences which have had, or are
reasonably likely to have, individually or in the aggregate, a Material Adverse
Effect on FNB, and (ii) the FNB Companies have not taken any action, or failed
to take any action, prior to the date of this Agreement, which action or
failure, if taken after the date of this Agreement, would represent or result in
a material breach or violation of any of the covenants and agreements of FNB
provided in Articles 7 or 8 of this Agreement.

         6.7      Tax Matters.

         (a)      All Tax Returns required to be filed by or on behalf of any of
the FNB Companies have been timely filed or requests for extensions have been
timely filed, granted, and have not expired for periods ended on or before
December 31, 2000, and on or before the date of the most recent fiscal year end
immediately preceding the Effective Time, except to the extent that all such
failures to file, taken together, are not reasonably likely to have a Material
Adverse Effect on FNB, and all Tax Returns filed are complete and accurate in
all material respects. All Taxes shown on filed Tax Returns have been paid.
There is no audit examination, deficiency, or refund Litigation with respect to
any Taxes that is reasonably likely to result in a determination that would
have, individually or in the aggregate, a Material Adverse Effect on FNB, except
as reserved against in the FNB Financial Statements delivered prior to the date
of this Agreement. All Taxes and other liabilities due with respect to completed
and settled examinations or concluded Litigation have been paid.

         (b)      Adequate provision for any Taxes due or, to the knowledge of
FNB, to become due for any of the FNB Companies for the period or periods
through and including the date of the respective FNB Financial Statements has
been made and is reflected on such FNB Financial Statements.

         (c)      Deferred Taxes of the FNB Companies have been adequately
provided for in the FNB Financial Statements.

         (d)      To the Knowledge of FNB, each of the FNB Companies is in
compliance with, and its records contain all information and documents
(including properly completed Internal Revenue Service Forms W-9) necessary to
comply with, all applicable information reporting and Tax withholding
requirements under federal, state and local Tax Laws, and such records identify
with specificity all accounts subject to backup withholding under Section 3406
of the Internal Revenue Code, except for such instances of noncompliance and
such omissions as are not reasonably likely to have, individually or in the
aggregate, a Material Adverse Effect on FNB.

         6.8      Compliance With Laws. FNB is duly registered as a financial
holding company under the BHC Act. Each FNB Company has in effect all Permits
necessary for it to own, lease, or operate its material Assets and to carry on
its business as now conducted, except for those Permits the absence of which are
not reasonably likely to have, individually or in the aggregate, a Material
Adverse Effect on FNB. None of the FNB Companies is presently in Default under
or in violation of any such Permit, other than Defaults which are not reasonably
likely to have, individually or in the aggregate, a Material Adverse Effect on
FNB. No FNB Company:

         (i)      is in violation of any Laws, Orders, or Permits applicable to
its business or employees conducting its business, except for violations which
are not reasonably likely to have, individually or in the aggregate, a Material
Adverse Effect on FNB; or

         (ii)     has received any notification or communication from any agency
or department of federal, state, or local government or any Regulatory Authority
or the staff thereof (i) asserting that any FNB Company is not in compliance
with any of the Laws or Orders which such governmental authority or


                                       17
   23

Regulatory Authority enforces, where such noncompliance is reasonably likely to
have, individually or in the aggregate, a Material Adverse Effect on FNB, (ii)
threatening to revoke any Permits, the revocation of which is reasonably likely
to have, individually or in the aggregate, a Material Adverse Effect on FNB, or
(iii) requiring any FNB Company to enter into or consent to the issuance of a
cease and desist order, formal agreement, directive, commitment, or memorandum
of understanding, or to adopt any board resolution or similar undertaking, which
restricts materially the conduct of its business, or in any manner relates to
its capital adequacy, its credit or reserve policies, its management or the
payment of dividends.

         6.9      Assets. Except as disclosed in Section 6.9 of the FNB
Disclosure Memorandum, the FNB Companies have good and marketable title, free
and clear of all Liens (except for those Liens which are not likely to have a
Material Adverse Effect on FNB or its Subsidiaries taken as a whole), to all of
their respective Assets. All material tangible properties used in the businesses
of the FNB Companies are in good condition, reasonable wear and tear excepted,
and are usable in the ordinary course of business consistent with FNB's past
practices. All Assets which are material to FNB's business on a consolidated
basis, held under leases or subleases by any of the FNB Companies, are held
under valid Contracts enforceable in accordance with their respective terms
(except as enforceability may be limited by applicable bankruptcy, insolvency,
reorganization, moratorium, or other Laws affecting the enforcement of
creditors' rights generally and except that the availability of the equitable
remedy of specific performance or injunctive relief is subject to the discretion
of the court before which any proceedings may be brought), and each such
Contract is in full force and effect. The FNB Companies currently maintain
insurance in amounts, scope, and coverage as disclosed in Section 6.9 of the FNB
Disclosure Memorandum. None of the FNB Companies has received written notice
from any insurance carrier that (i) such insurance will be canceled or that
coverage thereunder will be reduced or eliminated, or (ii) premium costs with
respect to such policies of insurance will be substantially increased. Except as
disclosed in Section 6.9 of the FNB Disclosure Memorandum, to the Knowledge of
FNB there are presently no occurrences giving rise to a claim under such
policies of insurance and no notices have been given by any FNB Company under
such policies.

         6.10     Legal Proceedings. Except as disclosed in Section 6.10 of the
FNB Disclosure Memorandum, there is no Litigation instituted or pending, or, to
the Knowledge of FNB, threatened (or unasserted but considered probable of
assertion and which if asserted would have at least a reasonable probability of
an unfavorable outcome) against any FNB Company, or against any Asset, employee
benefit plan, interest, or right of any of them, that is reasonably likely to
have, individually or in the aggregate, a Material Adverse Effect on FNB, nor
are there any Orders of any Regulatory Authorities, other governmental
authorities, or arbitrators outstanding against any FNB Company, that are
reasonably likely to have, individually or in the aggregate, a Material Adverse
Effect on FNB.

         6.11     Reports. Since January 1, 1996, or the date of organization if
later, each FNB Company has filed all reports and statements, together with any
amendments required to be made with respect thereto, that it was required to
file with Regulatory Authorities (except, in the case of state securities
authorities, failures to file which are not reasonably likely to have,
individually or in the aggregate, a Material Adverse Effect on FNB). As of its
respective date, each such report and document, including the financial
statements, exhibits, and schedules thereto, (i) complied in all material
respects with all applicable Laws, and (ii) did not, in all material respects,
contain any untrue statement of a material fact or omit to state a material fact
required to be stated therein or necessary to make the statements made therein,
in light of the circumstances under which they were made, not misleading, which
untrue statement of material fact or omission to state a material fact is likely
to have, individually, or in the aggregate, a Material Adverse Effect on FNB.

         6.12     Statements True and Correct. None of the information supplied
or to be supplied by any FNB Company or any Affiliate thereof for inclusion in
the Registration Statement will, when the


                                       18
   24

Registration Statement becomes effective, be false or misleading with respect to
any material fact, or omit to state any material fact necessary to make the
statements therein not misleading. None of the information supplied or to be
supplied by any FNB Company or any Affiliate thereof for inclusion in the Joint
Proxy Statement or any other documents to be filed by FNB or Promistar with the
SEC or any other Regulatory Authority in connection with the transactions
contemplated hereby will, at the respective time such documents are filed, and
with respect to the Joint Proxy Statement, when first mailed to the shareholders
of FNB or Promistar, be false or misleading with respect to any material fact,
or omit to state any material fact necessary to make the statements therein, in
light of the circumstances under which they were made, not misleading, or, in
the case of the Joint Proxy Statement or any amendment thereof or supplement
thereto, at the time of the FNB Shareholders' Meeting or the Promistar
Shareholders' Meeting, be false or misleading with respect to any material fact,
or omit to state any material fact necessary to correct any statement in any
earlier communication with respect to the solicitation of any proxy for the FNB
Shareholders' Meeting or the Promistar Shareholders' Meeting. All documents that
any FNB Company or any Affiliate thereof is responsible for filing with any
Regulatory Authority in connection with the transactions contemplated hereby
will comply as to form in all material respects with the provisions of
applicable Law.

         6.13     Accounting, Tax and Regulatory Matters. No FNB Company or any
Affiliate thereof has taken or agreed to take any action or has any Knowledge of
any fact or circumstance that is reasonably likely to (i) prevent the
transactions contemplated hereby, including the Merger, from qualifying for
pooling-of-interests accounting treatment or as a reorganization within the
meaning of Section 368(a)(2)(D) of the Internal Revenue Code, or (ii) materially
impede or delay receipt of any Consents of Regulatory Authorities referred to in
Section 9.1(b) of this Agreement or result in the imposition of a condition or
restriction of the type referred to in the last sentence of such Section.

         6.14     Environmental Matters.

         (a)      To the Knowledge of FNB, except as disclosed in Section 6.14
of the FNB Disclosure Memorandum, each FNB Company, its Participation
Facilities, and its Loan Properties are, and have been, in compliance with all
Environmental Laws, except for violations which are not reasonably likely to
have, individually or in the aggregate, a Material Adverse Effect on FNB.

         (b)      Except as disclosed in Section 6.14 of the FNB Disclosure
Memorandum, there is no Litigation pending, or, to the Knowledge of FNB,
threatened before any court, governmental agency, or authority or other forum in
which any FNB Company or any of its Loan Properties or Participation Facilities
(or any FNB Company in respect of any such Loan Property or Participation
Facility) has been or, with respect to threatened Litigation, may be named as a
defendant or potentially responsible party (i) for alleged noncompliance
(including by any predecessor) with any Environmental Law or (ii) relating to
the release into the environment of any Hazardous Material, whether or not
occurring at, on, under, or involving any of its Loan Properties or
Participation Facilities, except for such Litigation pending or threatened that
is not reasonably likely to have, individually or in the aggregate, a Material
Adverse Effect on FNB.

         (c)      To the Knowledge of FNB, except as disclosed in Section 6.14
of the FNB Disclosure Memorandum, there is no reasonable basis for any
Litigation of a type described above in Section 6.14(b), except such as is not
reasonably likely to have, individually or in the aggregate, a Material Adverse
Effect on FNB.

         (d)      To the Knowledge of FNB, except as disclosed in Section 6.14
of the FNB Disclosure Memorandum, during the period of (i) FNB's or any of its
Subsidiaries' ownership or operation of any of their respective properties, (ii)
FNB's or any of its Subsidiaries' participation in the management of any


                                       19
   25

Participation Facility, or (iii) FNB's or any of its Subsidiaries' holding a
security interest in a Loan Property, there have been no releases of Hazardous
Material in, on, under, or affecting any Participation Facility or Loan Property
of a FNB Company, except such as are not reasonably likely to have, individually
or in the aggregate, a Material Adverse Effect on FNB.

         6.15     Outstanding Promistar Common Stock. Except as disclosed in
Section 6.15 of the FNB Disclosure Memorandum, as of the date of this Agreement,
FNB Companies do not beneficially own any shares of Promistar Common Stock for
their own accounts (not including those held in a fiduciary or trust capacity
for, or on behalf of, unaffiliated third parties). During the term of this
Agreement, no FNB Company shall purchase or otherwise acquire beneficial
ownership of any additional Promistar Common Stock except pursuant to the terms
of this Agreement.

         6.16     Material Contracts. Except as set forth in the FNB SEC
Reports, no FNB Company is a party to or bound by any "material contract" as
such term is defined in Item 601(b)(10) of Regulation S-K of the SEC (each such
contract a "FNB Contract"). With respect to each FNB Contract and except as
disclosed in Section 6.16 of the FNB Disclosure Memorandum: (i) such FNB
Contract is in full force and effect; (ii) no FNB Company is in Default
thereunder; (iii) no FNB Company has repudiated or waived any material provision
of any such FNB Contract; and (iv) no other party to any such FNB Contract is,
to the Knowledge of FNB, in Default in any respect or has repudiated or waived
any material provision thereunder.

         6.17     Employee Benefit Plans.

         (a)      FNB has disclosed in Section 6.17 of the FNB Disclosure
Memorandum, and has delivered or made available to Promistar prior to the
execution of this Agreement copies in each case of: (i) all pension, retirement,
profit-sharing, deferred compensation, stock option, employee stock ownership,
severance pay, vacation, bonus, or other incentive plan, all other written
employee programs, arrangements, or agreements, all medical, vision, dental, or
other health plans, all life insurance plans, and all other employee benefit
plans or fringe benefit plans, including, without limitation, "employee benefit
plans" (as that term is defined in Section 3(3) of ERISA), currently adopted,
maintained by, sponsored in whole or in part by, or contributed to by any FNB
Company or ERISA Affiliate (as defined below) thereof for the benefit of
employees, retirees, dependents, spouses, directors, independent contractors, or
other beneficiaries and under which employees, retirees, dependents, spouses,
directors, independent contractors, or other beneficiaries are eligible to
participate (collectively, the "FNB Benefit Plans"); (ii) all insurance
contracts, annuity contracts and other funding vehicles relating to the FNB
Benefit Plans; (iii) all material agreements entered into with service providers
in connection with the FNB Benefit Plans; and (iv) summary plan descriptions,
favorable Internal Revenue Service determination letters for each FNB ERISA Plan
intended to be qualified under Section 401(a) of the Internal Revenue Code and
the most recently available Form 5500 annual reports, certified financial
statement and actuarial reports for the FNB Benefit Plans. Any of the FNB
Benefit Plans which is an "employee pension benefit plan" (as that term is
defined in Section 3(2) of ERISA), is referred to herein as a "FNB ERISA Plan."
Each FNB ERISA Plan which is also a "defined benefit plan" (as defined in
Section 4140) of the Internal Revenue Code) is referred to herein as a "FNB
Pension Plan." No FNB Pension Plan is or has been a multiemployer plan within
the meaning of Section 3(37) of ERISA. No FNB Benefit Plan is a multiple
employer plan within the meaning of Section 413(c) of the Internal Revenue Code
or is a multiple employer welfare arrangement within the meaning of Section
3(40) of ERISA. Since the date the foregoing documents were delivered or made
available to Promistar, no amendments to any FNB Benefit Plan have been made or
will be made prior to the Closing Date. Except as disclosed in Section 6.17 of
the FNB Disclosure Memorandum, FNB does not maintain any unwritten FNB Benefit
Plans. No FNB Company nor any ERISA Affiliate is a party to a collective
bargaining agreement. FNB has disclosed in Section 6.17 of the FNB Disclosure
Memorandum a complete and accurate list of (A) each ERISA


                                       20
   26

Affiliate, and (B) each FNB ERISA Plan that has not been adopted by each ERISA
Affiliate that maintains a separate payroll.

         (b)      Except as disclosed in Section 6.17 of the FNB Disclosure
Memorandum, all FNB Benefit Plans are in compliance with the applicable terms of
ERISA, the Internal Revenue Code, COBRA (as defined below) and any other
applicable Laws the breach or violation of which are reasonably likely to have,
individually or in the aggregate, a Material Adverse Effect on FNB, and each FNB
ERISA Plan which is intended to be qualified under Section 401(a) of the
Internal Revenue Code has received a favorable determination letter from the
Internal Revenue Service, and FNB is not aware of any circumstances likely to
result in revocation of any such favorable determination letter. Except as
disclosed in Section 6.17 of the FNB Disclosure Memorandum, to the Knowledge of
FNB, no FNB Company nor any ERISA Affiliate has any liability to the Internal
Revenue Service with respect to any FNB Benefit Plan, including any liability
imposed by Chapter 43 of the Internal Revenue Code, and no FNB Company has
engaged in a transaction with respect to any FNB Benefit Plan that, assuming the
taxable period of such transaction expired as of the date hereof, would subject
any FNB Company to a Tax imposed by either Section 4975 of the Internal Revenue
Code or Section 502(i) of ERISA in amounts which are reasonably likely to have,
individually or in the aggregate, a Material Adverse Effect on FNB.

         (c)      Except as disclosed in Section 6.17 of the FNB Disclosure
Memorandum, no FNB Pension Plan has any "unfunded current liability" (as that
term is defined in Section 302(d)(8)(A) of ERISA) and the fair market value of
the assets of any such plan exceeds the plan's "benefit liabilities," as that
term is defined in Section 4001(a)(16) of ERISA, when determined under actuarial
factors that would apply if the plan terminated in accordance with all
applicable legal requirements. Except as disclosed in Section 6.17 of the FNB
Disclosure Memorandum, since the date of the most recent actuarial valuation,
there has been (i) no material change in the financial position of any FNB
Pension Plan, (ii) no change in the actuarial assumptions with respect to any
FNB Pension Plan, and (iii) no increase in benefits under any FNB Pension Plan
as a result of plan amendments or changes in applicable Law which is reasonably
likely to have, individually or in the aggregate, a Material Adverse Effect on
FNB or materially adversely affect the funding status of any such plan. Neither
any FNB Pension Plan nor any "single-employer plan," within the meaning of
Section 4001(a)(15) of ERISA, currently or formerly maintained by any FNB
Company, or the single-employer plan of any entity which is considered one
employer with FNB under Section 4001 of ERISA or Section 414 of the Internal
Revenue Code or Section 302 of ERISA (whether or not waived) (an "ERISA
Affiliate") has an "accumulated funding deficiency" within the meaning of
Section 412 of the Internal Revenue Code or Section 302 of ERISA, which is
reasonably likely to have a Material Adverse Effect on FNB. No FNB Company has
provided, or is required to provide, security to a FNB Pension Plan or to any
single-employer plan of an ERISA Affiliate pursuant to Section 401(a)(29) of the
Internal Revenue Code.

         (d)      Within the six-year period preceding the Effective Time, no
liability under Subtitle C or D of Title IV of ERISA has been or is expected to
be incurred by any FNB Company with respect to any ongoing, frozen, or
terminated single-employer plan or the single-employer plan of any ERISA
Affiliate, which liability is reasonably likely to have a Material Adverse
Effect on FNB. No FNB Company has incurred any withdrawal liability with respect
to a multiemployer plan under Subtitle B of Title IV of ERISA (regardless of
whether based on contributions of an ERISA Affiliate), which liability is
reasonably likely to have a Material Adverse Effect on FNB. No notice of a
"reportable event," within the meaning of Section 4043 of ERISA for which the
30-day reporting requirement has not been waived, has been required to be filed
for any FNB Pension Plan or by any ERISA Affiliate within the 12-month period
ending on the date hereof. No FNB Company nor ERISA Affiliate has filed a notice
of intent to terminate any ERISA Pension Plan or has adopted any amendment to
treat such Plan as terminated. The Pension Benefit Guaranty Corporation has not
instituted proceedings to treat any ERISA Pension Plan as


                                       21
   27

terminated. No event has occurred or circumstance exists that may constitute
grounds under Section 4042 of ERISA for the termination of, or appointment of a
trustee to administer, any FNB Pension Plan.

         (e)      Except as disclosed in Section 6.17 of the FNB Disclosure
Memorandum, no FNB Company has any liability for retiree health and life
benefits under any of the FNB Benefit Plans other than health continuation
coverage required by the Consolidated Omnibus Budget Reconciliation Act of 1985
as amended and Sections 601 through 608 of ERISA ("COBRA") or by any similar
state law, and there are no restrictions on the rights of such FNB Company to
amend or terminate any such plan without incurring any liability thereunder,
which liability is reasonably likely to have a Material Adverse Effect on FNB.
There is no pending or, to the Knowledge of FNB, threatened complaint, claim
(other than a routine claim for benefits submitted by participants or
beneficiaries), proceeding, audit or investigation of any kind in or before any
court, tribunal, or governmental agency with respect to any FNB Benefit Plan.

         (f)      Except as disclosed in Section 6.17 of the FNB Disclosure
Memorandum, neither the execution and delivery of this Agreement nor the
consummation of the transactions contemplated hereby will (i) result in any
payment (including severance, unemployment compensation, golden parachute, or
otherwise) becoming due to any director or any employee of any FNB Company from
any FNB Company under any FNB Benefit Plan or otherwise, (ii) increase any
benefits otherwise payable under any FNB Benefit Plan, or (iii) result in any
acceleration of the time of payment or vesting of any such benefit, where such
payment, increase, or acceleration is reasonably likely to have, individually or
in the aggregate, a Material Adverse Effect on FNB.

         (g)      The actuarial present values of all accrued deferred
compensation entitlements (including entitlements under any executive
compensation, supplemental retirement, or employment agreement) of employees and
former employees of any FNB Company and their respective beneficiaries, other
than entitlements accrued pursuant to funded retirement plans subject to the
provisions of Section 412 of the Internal Revenue Code or Section 302 of ERISA,
have been fully reflected on the FNB Financial Statements to the extent required
by and in accordance with GAAP.

         (h)      All contributions and payments made or accrued with respect to
all FNB Benefit Plans are deductible under Sections 404 or 162 of the Internal
Revenue Code and, if not made, are properly reflected on the financial
statements of the FNB Companies and ERISA Affiliates. No event has occurred or
circumstance exists that could result in an increase in premium costs of insured
or self-insured FNB Benefit Plans that would have a Material Adverse Effect on
FNB. Levels of insurance reserves, trust funding and accrued liabilities with
respect to all ERISA Benefit Plans (to which such reserves or liabilities do or
should apply) are reasonable and sufficient to provide for all incurred but
unreported claims and any retroactive or prospective premium adjustments.

         6.18     Opinion of Financial Advisor. FNB has received the written
opinion of The Robinson-Humphrey Company, LLC, its financial advisor, to the
effect that, as of the date hereof, the consideration to be paid to the
Promistar shareholders, based upon and subject to the limitations set forth in
such opinion, is fair to the FNB shareholders from a financial point of view.

                                    ARTICLE 7
                    CONDUCT OF BUSINESS PENDING CONSUMMATION

         7.1      Mutual Covenants. From the date of this Agreement until the
earlier of the Effective Time or the termination of this Agreement, except as
expressly contemplated by this Agreement, (i) without the prior written consent
of Promistar (which consent shall not be unreasonably withheld or delayed), FNB
will not, and will cause each of its Subsidiaries not to, and (ii) without the
prior written consent of FNB


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(which consent shall not be unreasonably withheld or delayed), Promistar will
not, and will cause each of its Subsidiaries not to:

         (a)      take any action that would (i) adversely affect the ability of
any Party to obtain any necessary approvals of any Regulatory Authorities
required for the transactions contemplated hereby or (ii) adversely affect its
ability to perform any of its material obligations under this Agreement; or

         (b)      except as set forth on Section 7.1(b) of such Party's
Disclosure Memorandum, (i) enter into or amend any written employment, severance
or similar agreements or arrangements with any of its directors or executive
officers, (ii) enter into or amend any material written employment, severance or
similar agreements or arrangements with any of its officers or employees, or
(iii) grant any salary or wage increase or increase any employee benefit
(including incentive or bonus payments), except for (A) normal individual
increases in compensation to employees in the ordinary course of business
consistent with past practice or (B) other changes as are provided for herein or
as may be required by law or to satisfy contractual obligations existing as of
the date hereof or additional grants of awards to newly hired employees
consistent with past practice; provided, however, that each officer and employee
of Promistar entitled, pursuant to either Promistar's Key Employee Incentive
Compensation Plan of 1996 or Promistar's Annual Management Incentive Plan, to
receive a bonus at the end of the fiscal year in which the Closing occurs, shall
be paid a pro rata portion of such bonus at the Effective Time; or

         (c)      except as set forth on Section 7.1(c) of such Party's
Disclosure Memorandum, enter into or amend (except as may be required by
applicable law, to satisfy contractual obligations existing as of the date
hereof or amendments which, either individually or in the aggregate, would not
reasonably be expected to result in a material liability to FNB, Promistar or
their respective Subsidiaries) any pension, retirement, stock option, stock
purchase, savings, profit sharing, deferred compensation, consulting, bonus,
group insurance or other employee benefit, incentive or welfare contract, plan
or arrangement, or any trust agreement related thereto, in respect of any of its
directors, officers or other employees, including, without limitation, taking
any action that accelerates the vesting or exercise of any benefits payable
thereunder; or

         (d)      amend its Articles of Incorporation or Bylaws; or

         (e)      implement or adopt any change in its accounting principles,
practices or methods, other than as may be required by GAAP; or

         (f)      (i) knowingly take any action that would, or would be
reasonably likely to, prevent or impede the Merger from qualifying as a
"reorganization" within the meaning of Section 368(a) of the Code or for
"pooling of interests" accounting treatment under GAAP; or (ii) knowingly take
any action that is intended or is reasonably likely to result in (A) any of its
representations and warranties set forth in this Agreement being or becoming
untrue in any material respect at any time prior to the Effective Time, (B) any
of the conditions to the Merger set forth in Article 9 not being satisfied or
(C) a material violation of any provision of this Agreement except, in each
case, as may be required by applicable law; or

         (g)      agree or commit to do anything prohibited by this Section 7.1.

         7.2      Covenants of Promistar. From the date of this Agreement until
the earlier of the Effective Time or the termination of this Agreement, except
as expressly contemplated by this Agreement, Promistar covenants and agrees that
it will not, and will cause each of its Subsidiaries not to, do any of the
following without the prior consent (except as specifically provided otherwise
in this Agreement) of FNB:


                                       23
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         (a)      operate its business other than in the usual, regular and
ordinary course; or

         (b)      fail to use its reasonable best efforts to preserve intact its
business organization and Assets and maintain its rights and franchises; or

         (c)      fail to use its reasonable best efforts to maintain its
current employee relationships; or

         (d)      make any unsecured loan or other extension of credit to any
Person if, immediately after making such loan or extension of credit, such
Person would be indebted to the Promistar Companies, collectively, in an
aggregate amount in excess of $3,000,000, or make any fully secured loan to any
Person (except for loans secured by a first mortgage on single family
owner-occupied real estate and except for any loan to any Person who has
received from Promistar a commitment for a loan or extension of credit prior to
the date of this Agreement) if, immediately after making such loan, such Person
would be indebted to the Promistar Companies, collectively, in an aggregate
amount in excess of $5,000,000 (in either case FNB shall object thereto within
two business days, and the failure to provide a written objection within two
business days shall be deemed as the approval of FNB to make such loan or extend
such credit); or

         (e)      incur any additional debt obligation or other obligation for
borrowed money (other than indebtedness of a Promistar Company to another
Promistar Company) in excess of an aggregate of $1,000,000 (for the Promistar
Companies on a consolidated basis) except in the ordinary course of the business
of Promistar Subsidiaries consistent with past practices (it being understood
and agreed that the incurrence of indebtedness in the ordinary course of
business shall include, without limitation, creation of deposit liabilities,
purchases of federal funds, advances from the Federal Reserve Bank, and entry
into repurchase agreements fully secured by U.S. government or agency
securities, but shall not include advances from the Federal Home Loan Bank), or
impose, or suffer the imposition, on any Asset of any Promistar Company of any
Lien or permit any such Lien to exist (other than in connection with deposits,
repurchase agreements, bankers acceptances, "treasury tax and loan" accounts
established in the ordinary course of business, the satisfaction of legal
requirements in the exercise of trust powers, and Liens in effect as of the date
hereof that are disclosed in the Promistar Disclosure Memorandum); or

         (f)      except as disclosed in Section 7.2(f) of the Promistar
Disclosure Memorandum, repurchase, redeem, or otherwise acquire or exchange
(other than exchanges in the ordinary course under employee benefit plans),
directly or indirectly, any shares, or any securities convertible into any
shares, of the capital stock of Promistar; or

         (g)      except for this Agreement, or pursuant to the Stock Option
Agreement or pursuant to the exercise of stock options outstanding as of the
date hereof and pursuant to the terms thereof in existence on the date hereof,
or as disclosed in Section 7.2(g) of the Promistar Disclosure Memorandum, issue,
sell, pledge, encumber, authorize the issuance of, enter into any Contract to
issue, sell, pledge, encumber, or authorize the issuance of, or otherwise permit
to become outstanding, any additional Promistar Common Shares or any other
capital stock of any Promistar Company, or any stock appreciation rights, or any
option, warrant, conversion, or other right to acquire any such stock, or any
security convertible into any such stock; or

         (h)      adjust, split, combine, or reclassify any capital stock of any
Promistar Company or issue or authorize the issuance of any other securities in
respect of or in substitution for Promistar Common Shares, or sell, lease,
mortgage, or otherwise dispose of or otherwise encumber (i) any shares of
capital stock of any Promistar Subsidiary (unless any such shares of stock are
sold or otherwise transferred to another Promistar Company) or (ii) any Asset
other than in the ordinary course of business for reasonable and adequate
consideration; or


                                       24
   30

         (i)      except for purchases of United States Treasury securities or
United States Government agency securities, which in either case have maturities
of five years or less, and except as disclosed in Section 7.2(i) of the
Promistar Disclosure Memorandum, purchase any securities or make any material
investment, either by purchase of stock or securities, contributions to capital,
Asset transfers, or purchase of any Assets, in any Person other than a wholly
owned Promistar Subsidiary, or otherwise acquire direct or indirect control over
any Person, other than in connection with (i) foreclosures in the ordinary
course of business, (ii) acquisitions of control by a depository institution
Subsidiary in its fiduciary capacity, or (iii) the creation of new wholly owned
Subsidiaries organized to conduct or continue activities otherwise permitted by
this Agreement in which case FNB shall object thereto within two business days,
and the failure to provide written objection within two business days shall be
deemed to be approval of FNB to make such purchase or investment; or

         (j)      except as disclosed in Section 7.2(j) of the Promistar
Disclosure Memorandum, commence any Litigation other than in accordance with
past practice or settle any Litigation involving any liability of any Promistar
Company for material money damages or restrictions upon the operations of any
Promistar Company; or

         (k)      except in the ordinary course of business, modify, amend, or
terminate any material Contract other than renewals without material adverse
change of terms, or waive, release, compromise, or assign any material rights or
claims; or

         (l)      except as disclosed in Section 7.2(l) of the Promistar
Disclosure Memorandum, except for transactions in the ordinary course of
business consistent with past practice, make any investment in excess of
$250,000 either by purchase of stock or securities, contributions to capital,
property transfers, or purchase of any property or assets of any other
individual, corporation or other entity other than a wholly owned Subsidiary
thereof; or

         (m)      sell, transfer, mortgage, encumber or otherwise dispose of any
of its material properties or assets to any individual, corporation or other
entity other than a direct or indirect wholly owned Subsidiary, or cancel,
release or assign any indebtedness to any such Person or any claims held by any
such Person, except in the ordinary course of business consistent with past
practice or pursuant to contracts or agreements in force at the date of this
Agreement; or

         (n)      agree or commit to do anything prohibited by this Section 7.2.

         7.3      Covenants of FNB. From the date of this Agreement until the
earlier of the Effective Time or the termination of this Agreement, FNB
covenants and agrees that it shall continue to conduct its business and the
business of FNB Subsidiaries in a manner designed in its reasonable judgment, to
enhance the long-term value of the FNB Common Stock and the business prospects
of the FNB Companies; provided, that nothing in this Agreement shall prevent any
FNB Company from (i) discontinuing or disposing of any of its Assets or business
or (ii) acquiring all or any portion of the business of any other entity, if
such action is, in the judgment of FNB, desirable in the conduct of the business
of FNB and its Subsidiaries.

         7.4      Dividends.

         (a)      Promistar covenants and agrees that it shall not make,
declare, or pay any dividend or make any other distribution in respect of
Promistar's capital stock, except for (i) the acquisition of Promistar Common
Shares by Promistar in a fiduciary or trust capacity in the ordinary course of
business, (ii) regular and ordinary cash dividends on Promistar Common Shares in
an amount per share not to


                                       25
   31

exceed the per share amount of Promistar's most recent cash dividend as of the
date of this Agreement, and (iii) dividends from wholly owned Subsidiaries of
Promistar to Promistar or to another wholly owned Subsidiary of Promistar.

         (b)      FNB covenants and agrees that it shall not make, declare, or
pay any dividend or make any other distribution in respect of FNB's capital
stock, except for (i) quarterly cash dividends on FNB Common Stock in an amount
not to exceed the greater of (A) the rate payable on such FNB Common Stock as of
the date of this Agreement or (B) an amount equal to 40% of the after-tax net
income of FNB for FNB's fiscal quarter immediately preceding the record date for
such dividend, (ii) dividends payable on FNB Preferred Stock at a rate not
exceeding the rate provided for in the terms thereof, and (iii) dividends from
wholly owned Subsidiaries of FNB to FNB or to another wholly owned Subsidiary of
FNB, as applicable.

         (c)      After the date of this Agreement, each Party covenants and
agrees to coordinate with the other Party the declaration of any dividends in
respect of Promistar Common Stock and FNB Common Stock and the record dates and
payment dates relating thereto, it being the intention of the Parties that
holders of Promistar Common Stock or FNB Common Stock shall not receive two
dividends, or fail to receive one dividend, for any single calendar quarter with
respect to their shares of Promistar Common Stock and/or FNB Common Stock and
any shares of Promistar Common Stock any such holder receives in exchange
therefor in the Merger.

         7.5      Adverse Changes In Condition. Each Party agrees to give
written notice promptly to the other Party upon becoming aware of the occurrence
or impending occurrence of any event or circumstance relating to it or any of
its Subsidiaries which (i) is reasonably likely to have, individually or in the
aggregate, a Material Adverse Effect on it or (ii) would cause or constitute a
material breach of any of its representations, warranties, or covenants
contained herein, and to use its reasonable best efforts to prevent or promptly
to remedy the same.

         7.6      Reports. Each Party and its respective Subsidiaries shall file
all reports required to be filed by each of them with Regulatory Authorities
between the date of this Agreement and the Effective Time and shall deliver to
the other Party copies of all such reports promptly after the same are filed. If
financial statements are contained in any such reports filed with the SEC, such
financial statements will fairly present the consolidated financial position of
the entity filing such statements as of the dates indicated and the consolidated
results of operations, changes in shareholders' equity, and cash flows for the
periods then ended in accordance with GAAP (subject in the case of interim
financial statements to normal recurring year-end adjustments that are not
material and except for the absence of certain footnote information in the
unaudited financial statements). As of their respective dates, such reports
filed with the SEC will comply in all material respects with the Securities Laws
and will not contain any untrue statement of a material fact or omit to state a
material fact required to be stated therein or necessary in order to make the
statements therein, in light of the circumstances under which they were made,
not misleading. Any financial statements contained in any other reports to
another Regulatory Authority shall be prepared in accordance with the Laws
applicable to such reports.


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                                    ARTICLE 8
                              ADDITIONAL AGREEMENTS

         8.1      Registration Statement; Shareholder Approval.

         (a)      As soon as practicable after execution of this Agreement (in
no event later than August 15, 2001), FNB shall file the Registration Statement
with the SEC, and shall use its reasonable best efforts to cause the
Registration Statement to become effective under the 1933 Act and take any
action required to be taken under the applicable state blue sky or securities
Laws in connection with the issuance of the shares of FNB Common Stock upon
consummation of the Merger. Promistar shall furnish all information concerning
it and the holders of its capital stock as FNB may reasonably request in
connection with such action.

         (b)      Each of the Parties shall take, in accordance with applicable
Law and its respective articles of incorporation and bylaws, all action
necessary to convene, respectively, an appropriate meeting of the shareholders
of such Party, each such meeting to be held as promptly as practical after the
date hereof, for the purpose of voting upon approval of this Agreement and such
other related matters as each deems appropriate. Except as disclosed in Section
8.1(b) of the Promistar Disclosure Memorandum, in connection with such
shareholders' meetings, (i) each of the Parties shall mail the Joint Proxy
Statement to its respective shareholders, (ii) the Parties shall furnish to each
other all information concerning them that they may reasonably request in
connection with the Registration Statement and the Joint Proxy Statement, (iii)
the Board of Directors of each Party shall recommend (subject to compliance with
their fiduciary duties under applicable law as advised by counsel) to such
Party's shareholders the approval of this Agreement, (iv) each member of the
Board of Directors of each Party shall vote all of the shares of each of the
Parties beneficially owned by such director in favor of the approval of this
Agreement, and (v) the Board of Directors and officers of each Party shall
(subject to compliance with their fiduciary duties under applicable law as
advised by counsel) use their reasonable best efforts to obtain such
shareholders' approval.

         8.2      Applications. FNB shall use its reasonable best efforts to
prepare and file, not later than August 15, 2001, applications with all
Regulatory Authorities having jurisdiction over the transactions contemplated by
this Agreement seeking the requisite Consents necessary to consummate the
transactions contemplated by this Agreement and thereafter use its reasonable
best efforts to cause the Merger to be consummated as expeditiously as possible,
and Promistar shall cooperate in the preparation and, where appropriate, filing
of such applications. Further, FNB shall, prior to the Closing, prepare and file
with the National Association of Securities Dealers the required documents and
make payment of the required fees for the shares of FNB Common Stock to be
issued to holders of Promistar Common Stock in connection with the Merger.

         8.3      Filings With State Offices. Upon the terms and subject to the
conditions of this Agreement, FNB and Promistar shall, in connection with the
Closing, execute the Florida Articles of Merger and the Pennsylvania Articles of
Merger, and FNB shall cause the Florida Articles of Merger and the Pennsylvania
Articles of Merger to be filed with the Florida Secretary of State and the
Pennsylvania Secretary of State, respectively.

         8.4      Agreement as to Efforts to Consummate. Subject to the terms
and conditions of this Agreement, each Party agrees to use, and to cause its
Subsidiaries to use, its reasonable best efforts to take, or cause to be taken,
all actions, and to do, or cause to be done, all things necessary, proper, or
advisable under applicable Laws to consummate and make effective, as soon as
practicable after the date of this Agreement, the transactions contemplated by
this Agreement, including the use of their respective reasonable best efforts to
lift or rescind any Order adversely affecting its ability to consummate the


                                       27
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transactions contemplated herein and to cause to be satisfied the conditions
referred to in Article 9 of this Agreement; provided, that nothing herein shall
preclude either Party from exercising its rights under this Agreement. Each
Party shall use, and shall cause each of its Subsidiaries to use, its reasonable
best efforts to obtain all Permits and Consents of all third parties and
Regulatory Authorities necessary or desirable for the consummation of the
transactions contemplated by this Agreement.

         8.5      Access to Information; Confidentiality.

         (a)      From the date hereof to the earlier to occur of the Effective
Time or the termination of this Agreement pursuant to Article 10 hereof, upon
reasonable notice and subject to applicable Laws, FNB and Promistar shall afford
each other, and each other's accountants, counsel, and other representatives,
during normal working hours for the period of time prior to the Effective Time
or termination of this Agreement pursuant to Article 10 hereof, reasonable
access to all of its and its Subsidiaries' properties, books, contracts,
commitments, and records and, during such period, each shall furnish promptly to
the other Party (i) a copy of each report, schedule, and other document filed or
received by it or any of its Subsidiaries during such period pursuant to the
requirements of the Securities Laws, (ii) a copy of all filings made with any
Regulatory Authorities or other governmental entities in connection with the
transactions contemplated by this Agreement and all written communications
received from such Regulatory Authorities and governmental entities related
thereto, and (iii) all other information concerning either Party or its
respective Subsidiaries' business, properties and personnel as the other Party
may reasonably request, including reports of condition filed with Regulatory
Authorities. In this regard, without limiting the generality of the foregoing,
FNB and its Subsidiaries and Affiliates shall notify Promistar promptly upon the
receipt by it of any comments from the SEC, or its staff, and of any requests by
the SEC for amendments or supplements to the Registration Statement or for
additional information and will supply Promistar with copies of all
correspondence between it and its representatives, on the one hand, and the SEC
or the members of its staff or any other government official, on the other hand,
with respect to the Registration Statement. Each Party hereto shall, and shall
cause its advisors and representatives to (x) conduct its investigation in such
a manner which will not unreasonably interfere with the normal operations,
customers or employee relations of the other and shall be in accordance with
procedures established by the Parties having the due regard for the foregoing,
and (y) refrain from using for any purposes other than as set forth in this
Agreement, and shall treat as confidential, all information obtained by each
hereunder or in connection herewith and not otherwise known to them prior to the
Effective Time.

         (b)      FNB, the FNB Companies and their Affiliates will hold, and
will use their best efforts to cause their officers, directors, employees,
consultants, advisors, representatives, and agents to hold, in confidence,
unless compelled by judicial or other legal process, all confidential documents
and information furnished by Promistar to FNB, any FNB Company, or their
Affiliates in connection with the transactions contemplated by this Agreement,
including information provided in accordance with this Section 8.5, except to
the extent that such information can clearly be demonstrated by FNB to have been
(i) previously known on a nonconfidential basis by FNB, (ii) in the public
domain other than as a result of disclosure by FNB, any FNB Company, or any of
their Affiliates, or (iii) later lawfully acquired by FNB from sources other
than Promistar; provided, however, that FNB may disclose such information to its
officers, directors, employees, consultants, advisors, representatives, and
agents in connection with the transactions contemplated by this Agreement only
to the extent that such Persons who, in FNB's reasonable judgment, need to know
such information for the purpose of evaluating Promistar (provided that such
Persons shall be informed of the confidential nature of such information and
shall agree to be bound by the terms of this provision) and, in any event, such
disclosures shall be made only to the extent necessary for such purposes. If
this Agreement is terminated in accordance with Article 10 hereof, FNB, the FNB
Companies and their Affiliates shall maintain the confidence of such information
and will use their best efforts to cause its officers, directors, employees,
consultants, advisors, representatives, and

                                       28
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agents to, return to Promistar all documents and other materials, and all
copies made thereof, obtained by FNB, any FNB Company, or any of their
Affiliates in connection with this Agreement that are subject to this Section
8.5.

         (c)      Promistar and its Affiliates will hold, and will use their
best efforts to cause their officers, directors, employees, consultants,
advisors, representatives, and agents to hold, in confidence, unless compelled
by judicial or other legal process, all confidential documents and information
concerning FNB furnished to Promistar or its Affiliates in connection with the
transactions contemplated by this Agreement, including information provided in
accordance with this Section 8.5, except to the extent that such information can
clearly be demonstrated by Promistar to have been (i) previously known on a
nonconfidential basis by Promistar, (ii) in the public domain other than as a
result of disclosure by Promistar or any of its Affiliates, or (iii) later
lawfully acquired by Promistar from sources other than FNB; provided, however,
that Promistar may disclose such information to its officers, directors,
employees, consultants, advisors, representatives, and agents in connection with
the transactions contemplated by this Agreement only to the extent that such
Persons who, in Promistar's reasonable judgment, need to know such information
for the purpose of evaluating FNB (provided that such Persons shall be informed
of the confidential nature of such information and shall agree to be bound by
the terms of this provision) and, in any event, such disclosures shall be made
only to the extent necessary for such purposes. If this Agreement is terminated
in accordance with Article 10 hereof, Promistar and its Affiliates shall
maintain the confidence of such information and will, and will use their best
efforts to cause its officers, directors, employees, consultants, advisors,
representatives, and agents to, return to FNB all documents and other materials,
and all copies made thereof, obtained by Promistar or any of its Affiliates in
connection with this Agreement that are subject to this Section 8.5.

         8.6      Press Releases. Prior to the Effective Time, Promistar and FNB
shall, prior to any release or disclosure, consult with each other as to the
form and substance of any press release or other public disclosure materially
related to this Agreement or any other transaction contemplated hereby;
provided, that nothing in this Section 8.6 shall be deemed to prohibit any Party
from making any disclosure which its counsel deems necessary or advisable in
order to satisfy such Party's disclosure obligations imposed by Law.

         8.7      Current Information. During the period from the date of this
Agreement until the earlier to occur of the Effective Time or termination of
this Agreement pursuant to Article 10 hereof, each of Promistar and FNB shall,
and shall cause its representatives to, confer on a regular and frequent basis
with representatives of the other. Each of Promistar and FNB shall promptly
notify the other of (i) any material change in its business or operations, (ii)
any material complaints, investigations, or hearings (or communications
indicating that the same may be contemplated) of any Regulatory Authority, (iii)
the institution or threat of material Litigation involving such Party, or (iv)
the occurrence, or nonoccurrence, of an event or condition, the occurrence, or
nonoccurrence, of which would be reasonably expected to cause any of such
party's representations or warranties set forth herein to be untrue in any
respect as of the Effective Time; and in each case shall keep the other fully
informed with respect thereto.

         8.8      Other Actions. No Party shall, or shall permit any of its
Subsidiaries, if any, to take any action, except in every case as may be
required by applicable Law, that would or is intended to result in (i) any of
its representations and warranties set forth in this Agreement that are
qualified as to materiality being or becoming untrue, (ii) any of such
representations and warranties that are not so qualified becoming untrue in any
material manner having a Material Adverse Effect, (iii) any of the conditions
set forth in this Agreement not being satisfied or in a violation of any
material provision of this Agreement, or (iv) adversely affecting the ability of
any of them to obtain any of the Consents or Permits from Regulatory Authorities
(unless such action is required by sound banking practice).


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         8.9      No Solicitation.

         (a)      From and after the date of this Agreement and until the
earlier of the termination of this Agreement or the Effective Time, except in
compliance with this Section 8.9, Promistar will not, and will not permit its
directors, officers, employees, investment bankers, attorneys, accountants or
other representatives, agents or Affiliates to, directly or indirectly, (i)
solicit, initiate, or encourage any Acquisition Proposals; (ii) engage in
discussions with third parties, or negotiations concerning, or provide any
non-public information to any person or entity in connection with, any
Acquisition Proposal; or (iii) agree to, approve, recommend or otherwise endorse
or support any Acquisition Proposal. As used herein, the term "Acquisition
Proposal" shall mean any proposal relating to a possible (i) merger,
consolidation or similar transaction involving Promistar or any of its
Subsidiaries (other than a transaction with respect to which an acquisition
agreement has been executed and publicly announced as of the date hereof); (ii)
sale, lease or other disposition, directly or indirectly, involving Promistar or
any of its Subsidiaries representing, in the aggregate, 10% or more of the
Assets of Promistar on a consolidated basis; (iii) issuance, sale or other
disposition of (including by way of merger, consolidation, share exchange or any
similar transaction) securities (or options, rights or warrants to purchase or
securities convertible into, such securities) representing 10% or more of the
votes attached to the outstanding securities of Promistar; (iv) transaction with
Promistar in which any person shall acquire beneficial ownership (as such term
is defined in Rule 13d-3 under the Exchange Act), or the right to acquire
beneficial ownership, or any "group" (as such term is defined under the Exchange
Act) shall have been formed which beneficially owns or has the right to acquire
beneficial ownership of, 10% or more of the outstanding shares of Promistar
Common Stock; or (v) liquidation, dissolution, recapitalization or other similar
type of transaction with respect to Promistar; or (vi) transaction which is
similar in form, substance or purpose to any of the foregoing transactions;
provided, however, that the term "Acquisition Proposal" shall not include the
Merger and the transactions contemplated hereby. Promistar will, and will direct
all its directors, officers, employees, investment bankers, attorneys,
accountants and other representatives, agents and Affiliates to, immediately
cease any and all existing activities, discussions or negotiations with any
parties conducted heretofore with respect to any of the foregoing.

         (b)      Notwithstanding the provisions of Section 8.9(a) above, if a
corporation, limited liability company, limited liability partnership,
partnership, person or other entity or group (a "Third Party") after the date of
this Agreement submits to Promistar's Board of Directors an unsolicited, bona
fide, written Acquisition Proposal, and Promistar's Board of Directors
reasonably determines in good faith, after receipt of advice from outside legal
counsel that the failure to engage in discussions with the Third Party
concerning such Acquisition Proposal would likely cause Promistar's Board of
directors to breach its fiduciary duties to Promistar and its shareholders, and
after consultation with Keefe, Bruyette & Woods, Inc., or any other nationally
recognized investment bank, then, in such case, (i) Promistar may (A) furnish
information about its business to the Third Party under protection of an
appropriate confidentiality agreement containing customary limitations on the
use and disclosure of all non-public written or oral information furnished to
such Third Party, provided that Promistar must contemporaneously furnish to FNB
all such non-public information furnished to the Third Party and (B) negotiate
and participate in discussions and negotiations with such Third Party; and (ii)
if Promistar's Board of Directors determines that such an Acquisition Proposal
is a Superior Proposal (defined below), Promistar's Board of Directors may
(subject to the provisions of this Section 8.9) (A) withdraw or adversely modify
its approval or recommendation of the Merger and recommend such Superior
Proposal or (B) terminate this Agreement, in each case, at any time after the
second business day following delivery of written notice to FNB (a "Notice of
Superior Proposal") advising FNB that Promistar's Board of Directors has
received a Superior Proposal, identifying the Third Party and specifying the
material terms and conditions of such Superior Proposal. Promistar may take any
of the foregoing actions pursuant to the preceding sentence if, and only if, an
Acquisition Proposal that was a Superior Proposal continues to be a Superior
Proposal in light of any improved proposal submitted by FNB, considered in good
faith by Promistar and with the advice of a


                                       30
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financial advisor of nationally recognized reputation, including, without
limitation, Keefe, Bruyette & Woods, Inc., prior to the expiration of the two
business day period specified in the preceding sentence. Promistar shall provide
FNB with a final written notice, at least twenty-four (24) hours before
accepting any Superior Proposal. For purposes of this Agreement, "Superior
Proposal" means any unsolicited, bona fide, written Acquisition Proposal for
consideration consisting of cash (not subject to a financing contingency) and/or
securities, and otherwise on terms which Promistar's Board of Directors
determines (based on the written advice of a financial advisor of nationally
recognized reputation, including, without limitation, Keefe, Bruyette & Woods,
Inc.) are more favorable to Promistar's shareholders from financial point of
view than the Merger (or other revised proposal submitted by FNB as contemplated
above), after consultation with its outside legal counsel and that the Third
Party is reasonably likely to consummate the Superior Proposal on the terms
proposed. Nothing contained herein shall prohibit Promistar from taking, and
disclosing to its shareholders, a position required by Rule 14d-9(e) under the
Exchange Act prior to the second business day following FNB's receipt of a
Notice of Superior Proposal, provided that Promistar does not withdraw or modify
its position with respect to the Merger or approve or recommend an Acquisition
Proposal.

         (c)      Promistar will notify FNB immediately, and in any event within
24 hours, if (i) a bona fide Acquisition Proposal is made or is modified in any
respect (including any written material provided by the offeror, the principal
terms and conditions of any such Acquisition Proposal or modification thereto
and the identity of the offeror) or (ii) Promistar furnishes non-public
information to, or enters into discussions or negotiations with respect to an
acquisition Proposal with, any Third Party.

         (d)      In addition to the obligations of Promistar set forth in
paragraph (a), (b) and (c) of this Section 8.9, Promistar, as promptly as
practicable, will advise FNB orally and in writing of any request for
information which Promistar reasonably believes could lead to an Acquisition
Proposal or of any Acquisition Proposal, and the material terms and conditions
of such request, Acquisition Proposal or inquiry, Promistar will keep FNB
informed in all material respects of the status of any such request, Acquisition
Proposal or inquiry. In addition to the foregoing, Promistar will (i) provide
FNB with prior written notice of any meeting of Promistar's Board of Directors
(or any committee thereof) at which Promistar's Board of Directors is expected
to consider a Superior Proposal and (ii) provide FNB with prior written notice
of a meeting of Promistar's Board of Directors (or any committee thereof) at
which Promistar's Board of Directors is expected to recommend a Superior
Proposal to its shareholders and together with such notice a copy of the
definitive documentation relating to such Superior Proposal to the extent such
documentation is then available (and otherwise provide such definitive
documentation as soon as available).

         (e)      It is understood and agreed that, without limitation of
Promistar's obligations hereunder, any violation of this Section 8.9 by any
director, officer, Affiliate, investment bank, financial advisor, accountant,
attorney or other advisor or representative of Promistar, whether or not such
person or entity is purporting to act on behalf of Promistar, shall be deemed to
be a breach of this Section 8.9 by Promistar. Promistar agrees that, as of the
date hereof, it, its Affiliates and their respective directors, officers,
employees, investment bankers, attorneys, accountants and other representatives
and agents, shall immediately cease and cause to be terminated any existing
activities, discussions and negotiations with any Third Party (other than FNB
and its representatives) conducted heretofore with respect to any Acquisition
Proposal.

         8.10     Accounting and Tax Treatment. Each of the Parties undertakes
and agrees to use its reasonable best efforts to cause the Merger to qualify,
and to take no action which would cause the Merger to not qualify, for treatment
as a "reorganization" within the meaning of Section 368(a) of the Internal
Revenue Code for federal income tax purposes. FNB and Promistar undertake and
agree to use


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their respective reasonable best efforts to cause the Merger to qualify, and to
take no action that would cause the Merger to not qualify, for
pooling-of-interests accounting treatment.

         8.11     Articles of Incorporation Provisions. Each Promistar Company
shall take all necessary action to ensure that the entering into of this
Agreement and the consummation of the Merger and the other transactions
contemplated hereby do not and will not result in the grant of any rights to any
Person under the Articles of Incorporation, Bylaws, or other governing
instruments of any Promistar Company or restrict or impair the ability of FNB or
any of its Subsidiaries to vote, or otherwise to exercise the rights of a
shareholder with respect to, shares of any Promistar Company that may be
directly or indirectly acquired or controlled by it.

         8.12     Agreement of Affiliates. Promistar has disclosed in Section
8.12 of the Promistar Disclosure Memorandum all Persons whom it reasonably
believes are "affiliates" of Promistar as that term is defined in SEC Accounting
Series Releases 130 and 135 and in Rule 145 under the 1933 Act. Promistar shall
use its reasonable best efforts to cause each Person who may be deemed an
affiliate of Promistar to execute and deliver to FNB not later than the date of
mailing of the Joint Proxy Statement, a written agreement, substantially in the
form of Exhibit 2 hereto, providing that such Person will not sell, pledge,
transfer, or otherwise dispose of the shares of Promistar Common Stock held by
such Person except as contemplated by such agreement or by this Agreement and
will not sell, pledge, transfer, or otherwise dispose of the shares of FNB
Common Stock to be received by such Person upon consummation of the Merger
except in compliance with applicable provisions of the 1933 Act and the rules
and regulations thereunder and until such time as financial results covering at
least 30 days of combined operations of FNB and Promistar have been published
within the meaning of Section 201.01 of the SEC's Codification of Financial
Reporting Policies. Shares of FNB Common Stock issued to such affiliates of
Promistar in exchange for shares of Promistar Common Stock shall not be
transferable until such time as financial results covering at least 30 days of
combined operations of FNB and Promistar have been published within the meaning
of Section 201.01 of the SEC's Codification of Financial Reporting Policies,
regardless of whether each such affiliate has provided the written agreement
referred to in this Section 8.12 (and FNB shall be entitled to place restrictive
legends upon certificates for shares of FNB Common Stock issued to affiliates of
Promistar pursuant to this Agreement to enforce the provisions of this Section
8.12). FNB shall not be required to maintain the effectiveness of the
Registration Statement under the 1933 Act for the purposes of resale of FNB
Common Stock by such affiliates.

         8.13     Employment Contracts. At the Effective Time, FNB shall enter
into an employment agreement with each of Steven C. Ackmann and Kim Craig
containing such terms and conditions as mutually agreeable. In consideration of
the entering into such employment agreements, Steven C. Ackmann and Kim Craig
shall, at the Effective Time, cancel and terminate any employment agreements
entered into with Promistar.

         8.14     Indemnification.

         (a)      FNB shall indemnify, defend and hold harmless the present and
former directors, officers, employees, and agents of Promistar (each, an
"Indemnified Party") after the Effective Time against all costs, fees, or
expenses (including reasonable attorneys' fees), judgments, fines, penalties,
losses, claims, damages, liabilities, and amounts paid in settlement in
connection with any Litigation as incurred, in connection with any claim, action
or proceeding arising out of actions or omissions occurring at or prior to the
Effective Time (including the transactions contemplated by this Agreement) to
the same extent such Persons are indemnified as of the date of this Agreement by
Promistar under Promistar's Articles of Incorporation and Bylaws as in effect on
the date hereof, including provisions relating to advances of


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expenses incurred in the defense of any Litigation. Without limiting the
foregoing, in any case in which approval of FNB is required to effectuate any
indemnification, FNB shall direct or cause such FNB Company to direct, at the
election of the Indemnified Party, that the determination of any such approval
shall be made by independent counsel mutually agreed upon between FNB and the
Indemnified Party. FNB shall, and shall cause all other relevant FNB Companies,
to apply such rights of indemnification in good faith and to the fullest extent
permitted by applicable law.

         (b)      Prior to Closing, Promistar shall purchase for, and on behalf
of, its current and former officers and directors, extended coverage under the
current directors' and officers' liability insurance policy maintained by
Promistar to provide for continued coverage of such insurance for a period of
six years following the date of Closing with respect to matters occurring prior
to the Effective Time.

         (c)      If FNB or any of its successors or assigns shall consolidate
with or merge into any other Person and shall not be the continuing or surviving
Person of such consolidation or merger or shall transfer all or substantially
all of its assets to any Person, then and in each case, proper provision shall
be made so that the successors and assigns of FNB shall assume the obligations
set forth in this Section 8.14.

         (d)      The provisions of this Section 8.14 are intended to be for the
benefit of and shall be enforceable by, each Indemnified Party, his or her heirs
and representatives.

         8.15     Additional Reports. In accordance with Section 8.5, Promistar
and FNB shall each furnish to the other copies of any Promistar SEC Documents or
FNB SEC Documents, as the case may be, which it files with the SEC on or after
the date hereof, and Promistar and FNB, as the case may be, represents and
warrants that as of the respective dates thereof, such reports will not contain
any untrue statement of a material fact or omit to state a material fact
required to be stated therein or necessary to make the statement therein, in
light of the circumstances under which they were made, not misleading. Any
unaudited consolidated interim financial statements included in such reports
(including any related notes and schedules) will fairly present, in all material
respects, the financial position of Promistar or FNB, as the case may be, as of
the dates thereof and the results of operations and changes in financial
position or other information included therein for the periods or as of the
dates then ended, in each case in accordance with past practice and GAAP
consistently applied during the periods involved (except that such unaudited
financial statement exclude footnote disclosures necessary for a fair
presentation which would make them in compliance with GAAP, and such financial
statements are subject, where appropriate, to normal year-end adjustments).

         8.16     Exemption from Liability under Section 16(b).

         (a)      Provided that Promistar delivers to FNB the Section 16
Information (as defined below) with respect to Promistar prior to the Effective
Time, the Board of Directors of FNB, or a committee of Non-Employee Directors
thereof (as such term is defined for purposes of Rule 16b-3(d) under the
Exchange Act), will adopt a resolution in advance of the Effective Time
providing that the receipt by Promistar Insiders (as defined below) of FNB
Common Stock in exchange for shares of Promistar Common Stock, pursuant to the
transactions contemplated hereby and to the extent such securities are listed in
the Section 16 Information, are intended to be exempt from liability pursuant to
Rule 16b-3 under the Exchange Act.

         (b)      "Section 16 Information" shall mean information accurate in
all respects regarding Promistar Insiders, the number of shares of Promistar
Common Stock or other Promistar equity securities deemed to be beneficially
owned by each Promistar Insider and expected to be exchanged for FNB Common
Stock in connection with the Merger.


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   39

         (c)      "Promistar Insiders" shall mean those officers and directors
of Promistar who are subject to the reporting requirements of Section 16(a) of
the Exchange Act who are listed in the Section 16 Information.

         8.17     Right to Update Disclosure Memoranda. Each Party shall have
the right, without being in breach of its representations and warranties set
forth in this Agreement, to supplement or amend its Disclosure Memorandum, and
to add additional references to its Disclosure Memorandum to its representations
and warranties contained in this Agreement, with respect to any matter arising
after the date hereof or discovered between the date hereof and the date of the
Closing. A copy of the amended or supplemented Disclosure Memorandum and the
additional Disclosure Memorandum references shall be promptly provided to the
other Party. Any such amended or supplemented Disclosure Memorandum and
additional Disclosure Memorandum references shall not give the other Party the
right not to proceed to Closing, unless the facts underlying such amended or
supplemented Disclosure Memorandum or additional Disclosure Memorandum
references have a Material Adverse Effect.

                                   ARTICLE 9
                CONDITIONS PRECEDENT TO OBLIGATIONS TO CONSUMMATE

         9.1      Conditions to Obligations of Each Party. The respective
obligations of each Party to perform this Agreement and consummate the Merger
and the other transactions contemplated hereby are subject to the satisfaction
of the following conditions, unless waived by both Parties pursuant to Section
11.7 of this Agreement:

         (a)      Shareholder Approvals. The shareholders of each of Promistar
and FNB shall have approved this Agreement, and the consummation of the
transactions contemplated hereby, including the Merger, as and to the extent
required by Law.

         (b)      Regulatory Approvals. All Consents of, filings and
registrations with, and notifications to, all Regulatory Authorities required
for consummation of the Merger shall have been obtained or made and shall be in
full force and effect and all waiting periods required by Law shall have
expired. No Consent obtained from any Regulatory Authority which is necessary to
consummate the transactions contemplated hereby shall be conditioned or
restricted in a manner (including requirements relating to the raising of
additional capital or the disposition of Assets) which in the reasonable
judgment of the Board of Directors of either Party would so materially adversely
impact the economic or business benefits of the transactions contemplated by
this Agreement that, had such condition or requirement been known, such Party
would not, in its reasonable judgment, have entered into this Agreement.

         (c)      Consents and Approvals. Other than filing the Florida Articles
of Merger and the Pennsylvania Articles of Merger, each Party shall have
obtained any and all Consents required for consummation of the Merger (other
than those referred to in Section 9.1(b) of this Agreement or listed in Section
9.1(c) of the Promistar Disclosure Memorandum) or for the preventing of any
default under any Contract or Permit of such Party which, if not obtained or
made, is reasonably likely to have, individually or in the aggregate, a Material
Adverse Effect on such Party.

         (d)      Legal Proceedings. No court or governmental or regulatory
authority of competent jurisdiction shall have enacted, issued, promulgated,
enforced, or entered any Law or Order (whether temporary, preliminary, or
permanent) or taken any other action which prohibits, restricts, or makes
illegal consummation of the transactions contemplated by this Agreement.


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         (e)      Registration Statement. The Registration Statement shall have
been declared effective under the 1933 Act, and no stop orders suspending the
effectiveness of the Registration Statement shall have been issued, and no
action, suit, proceeding, or investigation by the SEC to suspend the
effectiveness thereof shall have been initiated and be continuing.

         (f)      Pooling of Interests. Ernst & Young LLP, FNB's independent
public accountants, shall have issued a letter, dated as of the Closing Date, to
each of Promistar and FNB to the effect that the Merger shall be accounted for
as a pooling-of-interests under GAAP.

         (g)      Tax Matters. Each Party shall have received a written opinion
or opinions from Smith, Gambrell & Russell, LLP, and in a form reasonably
satisfactory to such Parties (the "Tax Opinion"), to the effect that (i) the
Merger will constitute a reorganization within the meaning of Section 368(a) of
the Internal Revenue Code and (ii) the exchange in the Merger of Promistar
Common Stock for FNB Common Stock will not give rise to gain or loss to the
shareholders of Promistar with respect to such exchange (except to the extent of
any cash received). In rendering such Tax Opinion, such counsel shall be
entitled to rely upon representations of officers of Promistar and FNB
reasonably satisfactory in form and substance to such counsel.

         9.2      Conditions to Obligations of FNB. The obligations of FNB to
perform this Agreement and consummate the Merger and the other transactions
contemplated hereby are subject to the satisfaction of the following conditions,
unless waived by FNB pursuant to Section 11.7(a) of this Agreement:

         (a)      Representations and Warranties. The representations and
warranties of Promistar contained herein shall be true and correct both as of
the date of this Agreement and (except to the extent such representations and
warranties speak as of an earlier date) as of the Effective Time, except where
the failure of such representations and warranties to be so true and correct
(without giving effect to any limitation as to "materiality" or "Material
Adverse Effect" set forth therein) would not have, individually or in the
aggregate, a Material Adverse Effect on Promistar.

         (b)      Performance of Agreements and Covenants. Each and all of the
agreements and covenants of Promistar to be performed and complied with pursuant
to this Agreement and the other agreements contemplated hereby prior to the
Closing Date shall have been duly performed and complied with in all material
respects.

         (c)      Certificates. Promistar shall have delivered to FNB (i) a
certificate, dated as of the Closing Date and signed on its behalf by its chief
executive officer and its chief financial officer, to the effect that the
conditions of its obligations set forth in Section 9.2(a) and 9.2(b) of this
Agreement have been satisfied, and (ii) certified copies of resolutions duly
adopted by Promistar's Board of Directors and shareholders evidencing the taking
of all corporate action necessary to authorize the execution, delivery, and
performance of this Agreement, and the consummation of the transactions
contemplated hereby, all in such reasonable detail as FNB and its counsel shall
request.

         (d)      Affiliates Agreements. FNB shall have received from each
affiliate of Promistar the affiliates letter referred to in Section 8.12 of this
Agreement, to the extent necessary to assure in the reasonable judgment of FNB
that the transactions contemplated hereby will qualify for pooling-of-interests
accounting treatment.

         (e)      Non-Competition Agreements. FNB shall have received an
executed copy of a Non-Compete Agreement in the form attached to this Agreement
as Exhibit 3 from not less than 90% of the directors of Promistar who are not
executive officers of Promistar.


                                       35
   41

         (f)      Opinion of Counsel. FNB shall have received a written opinion
of Kirkpatrick & Lockhart LLP, counsel to Promistar, dated as of the Closing
Date, in substantially the form attached hereto as Exhibit 4.

         9.3      Conditions to Obligations of Promistar. The obligations of
Promistar to perform this Agreement and consummate the Merger and the other
transactions contemplated hereby are subject to the satisfaction of the
following conditions, unless waived by Promistar pursuant to Section 11.7(b) of
this Agreement:

         (a)      Representations and Warranties. The representations and
warranties of FNB contained herein shall be true and correct both as of the date
of this Agreement and (except to the extent such representations and warranties
speak as of an earlier date) as of the Closing Date, except where the failure of
such representations and warranties to be so true and correct (without giving
effect to any limitation as to "materiality" or "Material Adverse Effect" set
forth therein) would not have, individually or in the aggregate, a Material
Adverse Effect on FNB.

         (b)      Performance of Agreements and Covenants. Each and all of the
agreements and covenants of FNB to be performed and complied with pursuant to
this Agreement and the other agreements contemplated hereby prior to the Closing
Date shall have been duly performed and complied with in all material respects.

         (c)      Certificates. FNB shall have delivered to Promistar (i) a
certificate, dated as of the Closing Date and signed on its behalf by its chief
executive officer and its chief financial officer, to the effect that the
conditions of its obligations set forth in Section 9.3(a) and 9.3(b) of this
Agreement have been satisfied, and (ii) certified copies of resolutions duly
adopted by FNB's Board of Directors or the Executive Committee thereof
evidencing the taking of all corporate action necessary to authorize the
execution, delivery, and performance of this Agreement, and the consummation of
the transactions contemplated hereby, all in such reasonable detail as Promistar
and its counsel shall request.

          (d)     Opinion of Counsel. Promistar shall have received a written
opinion of Smith, Gambrell & Russell, LLP, counsel to FNB, dated as of the
Closing Date, in substantially the form attached hereto as Exhibit 5.

                                   ARTICLE 10
                                   TERMINATION

         10.1     Termination. Notwithstanding any other provision of this
Agreement, this Agreement may be terminated and the Merger abandoned at any time
prior to the Effective Time:

         (a)      By mutual written consent of the Board of Directors of FNB and
the Board of Directors of Promistar; or

         (b)      By the Board of Directors of either Party (provided that the
terminating Party (i) is not then in breach of any representations or warranties
contained in this Agreement such that the other Party would have the ability to
refuse to consummate the Merger pursuant to Section 9.2(a) or Section 9.3(a) of
this Agreement and (ii) is not in material breach of any covenant or other
agreement contained in this Agreement) in the event of an inaccuracy of any
representation or warranty of the other Party contained in this Agreement which
cannot be or has not been cured within 40 days after the giving of written
notice to the breaching Party of such inaccuracy and which inaccuracy would
provide the terminating Party the ability to refuse to consummate the Merger
pursuant to Section 9.2(a) or Section 9.3(a) of this Agreement; or


                                       36
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         (c)      By the Board of Directors of either Party in the event of a
material breach by the other Party of any covenant, agreement, or obligation
contained in this Agreement which breach cannot be or has not been cured within
40 days after the giving of written notice to the breaching Party of such
breach; or

         (d)      By the Board of Directors of either Party in the event (i) any
Consent of any Regulatory Authority required for consummation of the Merger and
the other transactions contemplated hereby shall have been denied by final
nonappealable action of such authority or if any action taken by such authority
is not appealed within the time limit for appeal, or (ii) the shareholders of
Promistar or FNB fail to vote their approval of this Agreement and the
transactions contemplated hereby as required by applicable Law; or

         (e)      By the Board of Directors of either Party in the event that
the Merger shall not have been consummated by March 31, 2002, if the failure to
consummate the transactions contemplated hereby on or before such date is not
caused by any breach of this Agreement by the Party electing to terminate
pursuant to this Section 10.1(e); or

         (f)      By the Board of Directors of either Party (provided that the
terminating Party is not then in breach of any representation or warranty
contained in this Agreement under the applicable standard set forth in Section
9.2(a) of this Agreement in the case of Promistar and Section 9.3(a) in the case
of FNB or in material breach of any covenant or other agreement contained in
this Agreement) in the event that any of the conditions precedent to the
obligations of such Party to consummate the Merger cannot be satisfied or
fulfilled by the date specified in Section 10.1(e) of this Agreement; or

         (g)      By Promistar on any date during the four business day period
commencing on the first day following the Approval Date, if both of the
following conditions are satisfied on such date:

                  (1)      the FNB Ratio on such date shall be less than 0.80;
         and

                  (2)      the FNB Ratio on such date shall be less than the
         difference obtained by subtracting 0.15 from the Index Ratio on such
         date;

         subject, however, to the following three sentences. If Promistar
determines not to consummate the Merger pursuant to this Section 10.1(g), it
shall give prompt written notice of its election to terminate to FNB, which
notice may be withdrawn at any time prior to the lapse of the four business day
period commencing on the Approval Date. During the five business day period
commencing on the date of its receipt of such notice (the "Adjustment Date"),
FNB shall have the option to elect to increase the Exchange Ratio to a number
equal to the Adjusted Exchange Ratio. The election contemplated by the preceding
sentence shall be made by giving notice to Promistar of such election and of the
Adjusted Exchange Ratio, whereupon no termination shall have occurred pursuant
to this Section 10.1(g), and this Agreement shall remain in effect in accordance
with its terms (except as the Exchange Ratio shall have been so modified), and
any references in this Agreement to "Exchange Ratio" shall thereafter be deemed
to refer to Adjusted Exchange Ratio.

         For purposes of this Section 10.1(g), the following terms shall have
the meanings indicated:

         "Adjusted Exchange Ratio" shall mean the lesser of:

                  (1)      a number (rounded to the nearest thousandth) obtained
         by dividing (A) the product of the Initial FNB Price, 0.80 and the
         Exchange Ratio (as then in effect) by (B) the FNB


                                       37
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         Price on the Approval Date, and

                  (2)      a number (rounded to the nearest one one-thousandth)
         equal to the product of (A) the Exchange Ratio (as then in effect)
         multiplied by (B) a fraction, the numerator of which is the Index Radio
         on the Approval Date less 0.15, and the denominator of which is the FNB
         Ratio on the Approval Date.

         "FNB Price," with respect to any particular date, shall mean the
average closing price per share of FNB Common Stock, as reported by Nasdaq, for
the five most recent trading days ending on the last trading date prior to such
date.

         "FNB Ratio," with respect to any particular date, shall mean the
quotient obtained by dividing the FNB Price on such date by the Initial FNB
Price.

         "Initial FNB Price" shall mean $24.952.

         "Index Group" shall mean the bank and bank holding companies listed on
Exhibit 6 hereto, the common stocks of all of which shall be publicly traded and
as to which there shall not have been, after the date of this Agreement and
before the Adjustment Date, any public announcement of a proposal for such
entity to be acquired or for such entity to acquire another entity in
transactions with a value exceeding 25% of the acquiror's market capitalization.
In the event that one or more of such entities are removed from the Index Group,
the weights (which have been determined based upon market capitalizations on May
18, 2001) shall be redistributed proportionately (based on market
capitalizations on May 18, 2001) for purposes of determining the Index Price.
The weight attributed to each of the entities composing the Index Group is set
forth on Exhibit 6 hereto. If any entity belonging to the Index Group or FNB
declares or effects a stock dividend, reclassification, recapitalization,
split-up, combination, exchange of shares, or similar transaction between the
date hereof and the Adjustment Date, the prices for the common stock of such
entity or FNB shall be appropriately adjusted for the purposes of applying this
Section 10.1(g).

         "Index Price," with respect to any particular date, shall mean the
weighted average (weighted in accordance with the "Percentage Weighting" set
forth on Exhibit 6 hereto) of the closing sales prices of the companies
composing the Index Group (as reported by The Wall Street Journal) for each of
the five most recent trading days ending on the last trading date prior to such
date.

         "Initial Index Price" shall mean the Index Price on May 19, 2001.

         "Index Ratio," with respect to any particular date, shall mean the
quotient obtained by dividing the Index Price on such date by the Initial Index
Price.


                                       38
   44

         10.2     Effect of Termination.

         (a)      In the event of the termination and abandonment of this
Agreement pursuant to Section 10.1 of this Agreement, this Agreement shall
become void and have no effect, except that (i) the provisions of this Section
10.2 and Sections 8.5 and 11.1 of this Agreement shall survive any such
termination and abandonment, and (ii) a termination pursuant to Sections 10.1(b)
or 10.1(c), of this Agreement shall not relieve the breaching Party from
liability for an uncured willful breach of a representation, warranty, covenant,
or agreement giving rise to such termination; provided, further, that in the
event of any termination of this Agreement following the occurrence of an
Initial Triggering Event (as defined in the Stock Option Agreement), FNB shall
be entitled to a cash payment from Promistar in an amount equal to $1,000,000
upon the occurrence of any Subsequent Triggering Event (as defined in the Stock
Option Agreement) within twelve (12) months following the date of such
termination (or such longer period as shall exist under the Stock Option
Agreement until the occurrence of an Exercise Termination Date (as defined in
the Stock Option Agreement).

         (b)      In the event this Agreement is terminated as a result of FNB's
failure to satisfy any of its representations, warranties or covenants set forth
herein, FNB shall reimburse Promistar for its reasonable out-of-pocket expenses
relating to the Merger in an amount not to exceed $250,000, which amount shall
not be deemed an exclusive remedy or liquidated damages.

         10.3     Non-Survival of Representations and Covenants. The respective
representations and warranties of the Parties shall not survive the Effective
Time. All agreements of the Parties to this Agreement which by their terms are
to be performed following the Effective Time shall survive the Effective Time
until performed in accordance with their terms.

                                   ARTICLE 11
                                  MISCELLANEOUS

         11.1     Definitions.

         (a)      Except as otherwise provided herein, the capitalized terms set
forth below shall have the following meanings:

         "1933 Act" shall mean the Securities Act of 1933, as amended.

         "1934 Act" shall mean the Securities Exchange Act of 1934, as amended.

         "Acquisition Proposal" shall have the meaning set forth in Section 8.9
of this Agreement.

         "Affiliate" of a Person shall mean any other Person directly, or
indirectly through one or more intermediaries, controlling, controlled by or
under common control with such Person.

         "Agreement" shall mean this Agreement and Plan of Merger, including the
Exhibits delivered pursuant hereto and incorporated herein by reference.

         "Approval Date" shall mean the date on which the last of the following
occurs: (i) the effective date (including expiration of any applicable waiting
period required by Law) of the last required Consent of any Regulatory Authority
having authority over and approving or exempting the Merger, (ii) the date on
which the shareholders of Promistar approve this Agreement to the extent that
such approval is


                                       39
   45

required by applicable Law; and (iii) the date on which the shareholders of FNB
approve this Agreement to the extent that such approval is required by
applicable Law.

         "Assets" of a Person shall mean all of the assets, properties,
businesses, and rights of such Person of every kind, nature, character, and
description, whether real, personal, or mixed, tangible or intangible, accrued
or contingent, or otherwise relating to or utilized in such Person's business,
directly or indirectly, in whole or in part, whether or not carried on the books
and records of such Person, and whether or not owned in the name of such Person
or any Affiliate of such Person and wherever located.

         "BHC Act" shall mean the federal Bank Holding Company Act of 1956, as
amended.

         "Closing" shall have the meaning set forth in Section 1.2 of this
Agreement.

         "Consent" shall mean any consent, approval, authorization, clearance,
exemption, waiver, or similar affirmation by any Person.

         "Contract" shall mean any written agreement, commitment, contract,
note, bond, mortgage, indenture, instrument, lease, obligation, or plan of any
kind or character, or other document to which any Person is a party or that is
binding on any Person or its capital stock or Assets.

         "Default" shall mean (i) any breach or violation of or default under
any Contract, (ii) any occurrence of any event that with the passage of time or
the giving of notice or both would constitute a breach or violation of or
default under any Contract, or (iii) any occurrence of any event that with or
without the passage of time or the giving of notice would give rise to a right
to terminate or revoke, change the current terms of, or renegotiate, or to
accelerate, increase, or impose any liability under, any Contract where, in any
such event, such default is reasonably likely to have a Material Adverse Effect
on a Party.

         "Effective Time" shall have the meaning set forth in Section 1.3 of
this Agreement.

         "Environmental Laws" shall mean all Laws relating to pollution or
protection of human health or the environment (including ambient air, surface
water, ground water, land surface, or subsurface strata) and which are
administered, interpreted, or enforced by the United States Environmental
Protection Agency and state and local agencies with jurisdiction over, and
including common law in respect of, pollution or protection of the environment,
including the Comprehensive Environmental Response Compensation and Liability
Act, as amended, 42 U.S.C. 9601 et seq., the Resource Conservation and Recovery
Act, as amended, 42 U.S.C. 6901 et seq., and other Laws relating to emissions,
discharges, releases, or threatened releases of any Hazardous Material, or
otherwise relating to the manufacture, processing, distribution, use, treatment,
storage, disposal, transport, or handling of any Hazardous Material.

         "ERISA" shall mean the Employee Retirement Income Security Act of 1974,
as amended.

         "Exchange Agent" shall have the meaning set forth in Section 4.1 of
this Agreement.

         "Exchange Ratio" shall have the meaning set forth in Section 3.1(b) of
this Agreement.

         "Exhibits" 1, 2, 3, 4, 5 and 6 shall mean the Exhibits so marked,
copies of which are attached to this Agreement. Such Exhibits are hereby
incorporated by reference herein and made a part hereof, and may be referred to
in this Agreement and any other related instrument or document without being
attached hereto.


                                       40
   46

         "FBCA" shall mean the Florida Business Corporation Act.

         "Florida Articles of Merger" shall mean the Articles of Merger to be
executed by the Parties and filed with the Secretary of State of the State of
Florida relating to the Merger as contemplated by Section 1.3 of this Agreement.

         "FNB" shall have the meaning set forth in the first paragraph of this
Agreement.

         "FNB Capital Stock" shall have the meaning set forth in Section 6.3 of
this Agreement.

         "FNB Common Stock" shall mean the common stock of FNB.

         "FNB Companies" shall mean, collectively, FNB and all FNB Subsidiaries.

         "FNB Contract" shall have the meaning set forth in Section 6.16 of this
Agreement.

         "FNB Disclosure Memorandum" shall mean the written information entitled
"FNB Corporation Disclosure Memorandum" delivered prior to the date of this
Agreement to Promistar, and all amendments or supplements thereto occurring
between the date of this Agreement and the date of the Closing, describing in
reasonable detail the matters contained therein and, with respect to each
disclosure made therein, specifically referencing each Section of this Agreement
under which such disclosure is being made. Information disclosed with respect to
one Section shall not be deemed to be disclosed for purposes of any other
Section not specifically referenced with respect thereto.

         "FNB Financial Statements" shall mean certain financial statements of
FNB consisting of (i) the consolidated balance sheets and the related statements
of income, changes in shareholders' equity, and cash flows (including related
notes and schedules, if any) as of and for each of the three years ended
December 31, 2000, 1999, and 1998, as filed by FNB in SEC Documents, and (ii)
the consolidated balance sheets and related statements of income, changes in
shareholders' equity, and cash flows (including related notes and schedules, if
any) included in SEC Documents filed with respect to any period ended subsequent
to December 31, 2000.

         "FNB Preferred Stock" shall mean the preferred stock of FNB.

         "FNB SEC Reports" shall have the meaning set forth in Section 6.5(a) of
this Agreement.

         "FNB Shareholders' Meeting" shall mean the meeting of the shareholders
of FNB to be held pursuant to Section 8.1 of this Agreement, including any
adjournment or adjournments thereof.

         "FNB Subsidiaries" shall mean the Subsidiaries of FNB, which shall
include any corporation, bank, savings association, or other organization
acquired as a Subsidiary of FNB in the future and owned by FNB at the Effective
Time.

         "GAAP" shall mean generally accepted accounting principles in the
United States, consistently applied during the periods involved applicable to
banks or bank holding companies, as the case may be.

         "Hazardous Material" shall mean (i) any hazardous substance, hazardous
material, hazardous waste, regulated substance, or toxic substance (as those
terms are defined by any applicable Environmental Laws) and (ii) any chemicals,
pollutants, contaminants, petroleum, petroleum products, or


                                       41
   47

oil (and specifically shall include asbestos requiring abatement, removal, or
encapsulation pursuant to the requirements of governmental authorities, and any
polychlorinated biphenyls).

         "HSR Act" shall mean Section 7A of the Clayton Act, as added by Title
II of the Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended, and
the rules and regulations promulgated thereunder.

         "Indemnified Party" shall have the meaning set forth in Section 8.14 of
this Agreement.

         "Internal Revenue Code" shall mean the Internal Revenue Code of 1986,
as amended, and the rules and regulations promulgated thereunder.

         "Joint Proxy Statement" shall mean the proxy statement used by
Promistar and FNB to solicit the approval of their respective shareholders of
the transactions contemplated by this Agreement, which shall include the
prospectus of FNB relating to the issuance of the FNB Common Stock to holders of
Promistar Common Stock.

         "Knowledge" as used with respect to a Person (including references to
such Person being aware of a particular matter) shall mean the personal
knowledge of the chairman, president, chief financial officer, chief accounting
officer, chief credit officer, or any executive vice president of such Person.

         "Law" shall mean any code, law, ordinance, regulation, reporting or
licensing requirement, rule, or statute applicable to a Person or its Assets,
liabilities, or business, including those promulgated, interpreted, or enforced
by any Regulatory Authority.

         "Lien" with respect to any Asset, shall mean any conditional sale
agreement, default of title, easement, encroachment, encumbrance, hypothecation,
infringement, lien, mortgage, pledge, reservation, restriction, security
interest, title retention, or other security arrangement, or any adverse right
or interest, charge, or claim of any nature whatsoever of, on, or with respect
to any property or property interest, other than (i) Liens for current property
Taxes not yet due and payable or being contested in good faith, (ii) for
depository institution Subsidiaries of a Party, pledges to secure deposits, and
(iii) other Liens incurred in the ordinary course of the banking business.

         "Litigation" shall mean any action, arbitration, cause of action,
claim, complaint, criminal prosecution, demand letter, governmental or other
examination or investigation, hearing, inquiry, administrative or other
proceeding, or notice by any Person alleging potential liability.

         "Loan Property" shall mean any property owned, leased, or operated by
the Party in question or by any of its Subsidiaries or in which such Party or
its Subsidiary holds a security or other interest (including an interest in a
fiduciary capacity), and, where required by the context, includes the owner or
operator of such property, but only with respect to such property.

         "market price" shall have the meaning set forth in Section 3.4 of this
Agreement.

         "Material Adverse Effect" on a Party shall mean an event, change, or
occurrence which, individually or together with any other event, change, or
occurrence, has a material adverse impact on (i) the financial position,
business, or results of operations of such Party and its Subsidiaries, taken as
a whole, or (ii) the ability of such Party to perform its obligations under this
Agreement or to consummate the Merger or the other transactions contemplated by
this Agreement, provided that "Material Adverse Effect" shall not be deemed to
include the impact of (a) changes in banking and similar Laws of general
applicability or interpretations thereof by courts or governmental authorities,
(b) changes in GAAP or


                                       42
   48

regulatory accounting principles generally applicable to banks and their holding
companies, (c) actions and omissions of a Party (or any of its Subsidiaries)
taken with the prior informed consent of the other Party in contemplation of the
transactions contemplated hereby, (d) circumstances affecting regional bank
holding companies generally, or (e) the Merger and compliance with the
provisions of this Agreement on the operating performance of the Parties.

         "Merger" shall have the meaning set forth in the Preamble of this
Agreement.

         "Nasdaq" shall mean the Nasdaq Stock Market, Inc.

         "Order" shall mean any decree, injunction, judgment, order, decision or
award, ruling, or writ of any federal, state, local, or foreign or other court,
arbitrator, mediator, tribunal, administrative agency, or Regulatory Authority.

         "Participation Facility" shall mean any facility or property in which
the Party in question or any of its Subsidiaries participates in the management
and, where required by the context, said term means the owner or operator of
such facility or property, but only with respect to such facility or property.

         "Party" shall mean either Promistar or FNB, and "Parties" shall mean
Promistar and FNB.

         "PBCL" shall mean the Pennsylvania Business Corporation Law.

         "Pennsylvania Articles of Merger" shall mean the Articles of Merger to
be executed by the Parties and filed with the Secretary of State of Pennsylvania
relating to the Merger as contemplated by Section 1.3 of this Agreement.

         "Permit" shall mean any federal, state, local, and foreign governmental
approval, authorization, certificate, easement, filing, franchise, license,
notice, permit, or right to which any Person is a party or that is or may be
binding upon or inure to the benefit of any Person.

         "Person" shall mean a natural person or any legal, commercial, or
governmental entity, such as, but not limited to, a corporation, general
partnership, joint venture, limited partnership, limited liability company,
trust, business association, group acting in concert, or any person acting in a
representative capacity.

         "Promistar" shall have the meaning set forth in the first paragraph of
this Agreement.

         "Promistar Benefits Plans" shall have the meaning set forth in Section
5.17(a) of this Agreement.

         "Promistar Common Stock" shall mean the $5.00 par value common stock of
Promistar.

         "Promistar Companies" shall mean, collectively, Promistar and all
Promistar Subsidiaries.

         "Promistar Contract" shall have the meaning set forth in Section 5.16.

         "Promistar Disclosure Memorandum" shall mean the written information
entitled "Promistar Disclosure Memorandum" delivered prior to the date of this
Agreement to FNB, and all amendments and supplements thereto occurring between
the date of this Agreement and the date of the Closing, describing in reasonable
detail the matters contained therein and, with respect to each disclosure made
therein, specifically referencing each Section of this Agreement under which
such disclosure is being made.


                                       43
   49

Information disclosed with respect to one Section shall not be deemed to be
disclosed for purposes of any other Section not specifically referenced with
respect thereto.

         "Promistar ERISA Plan" shall have the meaning set forth in Section
5.17(a) of this Agreement.

         "Promistar Financial Statements" shall mean certain financial
statements of Promistar consisting of (i) the consolidated balance sheets and
the related statements of income, changes in shareholders' equity, and cash
flows (including related notes and schedules, if any) as of and for each of the
three years ended December 31, 2000, 1999 and 1998, as filed by Promistar in SEC
Documents, and (ii) the consolidated balance sheets and related statements of
income, changes in shareholders' equity, and cash flows (including related notes
and schedules, if any) included in SEC Documents filed with respect to any
period ended subsequent to December 31, 2000.

         "Promistar Options" shall have the meaning set forth in Section 3.5(a)
of this Agreement.

         "Promistar SEC Reports" shall have the meaning set forth in Section
5.5(a) of this Agreement.

         "Promistar Shareholders' Meeting" shall mean the meeting of the
shareholders of Promistar to be held pursuant to Section 8.1 of this Agreement,
including any adjournment or adjournments thereof.

         "Promistar Stock Plans" shall have the meaning set forth in Section
3.5(a) of this Agreement.

         "Promistar Subsidiaries" shall mean the Subsidiaries of Promistar,
which shall include the Promistar Subsidiaries described in Section 5.4 of this
Agreement and any corporation, bank, savings association, or other organization
acquired as a Subsidiary of Promistar in the future and owned by Promistar at
the Effective Time.

         "Registration Statement" shall mean the Registration Statement on Form
S-4, or other appropriate form, including any pre-effective or post-effective
amendments or supplements thereto, filed with the SEC by FNB under the 1933 Act
with respect to the shares of FNB Common Stock to be issued to the shareholders
of Promistar in connection with the transactions contemplated by this Agreement.

         "Regulatory Authorities" shall mean, collectively, the Federal Trade
Commission, the United States Department of Justice, the Board of the Governors
of the Federal Reserve System, the Office of the Comptroller of the Currency,
the Federal Deposit Insurance Corporation, the SEC, NASD, Nasdaq and all state
regulatory agencies having jurisdiction over the Parties and their respective
Subsidiaries.

         "Rights" shall mean all arrangements, calls, commitments, options,
rights to subscribe to, scrip, understandings, warrants, or other binding
obligations of any character whatsoever relating to, or securities or rights
convertible into or exchangeable for, shares of the capital stock of a Person or
any contract, commitments or other arrangements by which a Person is or may be
bound to issue additional shares of its capital stock or options, warrants,
rights to purchase or acquire any additional shares of its capital stock, or
options, warrants, or rights to purchase or acquire any additional shares of its
capital stock.

         "SEC" shall mean the Securities and Exchange Commission.

         "SEC Documents" shall mean all forms, proxy statements, registration
statements, reports, schedules, and other documents filed, or required to be
filed, by a Party or any of its Subsidiaries with any Regulatory Authority
pursuant to the Securities Laws.


                                       44
   50

         "Securities Laws" shall mean the Securities Act of 1933, as amended
(the "1933 Act"), the Securities Exchange Act of 1934, as amended (the "1934
Act"), the Investment Company Act of 1940, as amended, the Investment Advisors
Act of 1940, as amended, the Trust Indenture Act of 1939, as amended, and the
rules and regulations of any Regulatory Authority promulgated thereunder.

         "Stock Option Agreement" shall have the meaning set forth in the
Preamble of this Agreement.

         "Subsidiaries" shall mean all those corporations, banks, associations,
or other entities of which the entity in question owns or controls 50% or more
of the outstanding equity securities either directly or through an unbroken
chain of entities as to each of which 50% or more of the outstanding equity
securities is owned directly or indirectly by its parent; provided, there shall
not be included any such entity acquired through foreclosure or any such entity
the equity securities of which are owned or controlled in a fiduciary capacity.

         "Tax" or "Taxes" shall mean all federal, state, local, and foreign
taxes, charges, fees, levies, imposts, duties, or other assessments, including
income, gross receipts, excise, employment, sales, use, transfer, license,
payroll, franchise, severance, stamp, occupation, windfall profits,
environmental, federal highway use, commercial rent, customs duties, capital
stock, paid-up capital, profits, withholding, Social Security, single business
and unemployment, disability, real property, personal property, registration, ad
valorem, value added, alternative or add-on minimum, estimated, or other tax or
governmental fee of any kind whatsoever, imposed or required to be withheld by
the United States or any state, local, foreign government or subdivision or
agency thereof, including any interest, penalties or additions thereto.

         "Tax Opinion" shall have the meaning set forth in Section 9.1(g) of
this Agreement.

         "Taxable Period" shall mean any period prescribed by any governmental
authority, including the United States or any state, local, foreign government
or subdivision or agency thereof for which a Tax Return is required to be filed
or Tax is required to be paid.

         "Tax Return" shall mean any report, return, information return, or
other information required to be supplied to a taxing authority in connection
with Taxes, including any return of an affiliated or combined or unitary group
that includes a Party or its Subsidiaries.

         (b)      Any singular term in this Agreement shall be deemed to include
the plural, and any plural term the singular. Whenever the words "include,"
"includes," or "including" are used in this Agreement, they shall be deemed
followed by the words "without limitation."

         11.2     Expenses.

         (a)      Except as otherwise provided in this Section 11.2 and Section
10.2, each of FNB and Promistar shall bear and pay all direct costs and expenses
incurred by it or on its behalf in connection with the transactions contemplated
hereunder, including filing, registration, and application fees, printing fees,
and fees and expenses of its own financial or other consultants, investment
bankers, accountants, and counsel, except that each of FNB and Promistar shall
each bear and pay one-half of the printing costs incurred in connection with the
printing of the Registration Statement and the Joint Proxy Statement.

         (b)      Nothing contained in this Section 11.2 shall constitute or
shall be deemed to constitute an exclusive remedy or liquidated damages for the
willful breach by a Party of the terms of this Agreement or otherwise limit the
rights of the nonbreaching Party.


                                       45
   51

         11.3     Brokers and Finders. Each of the Parties represents and
warrants that no action has been taken by it that would give rise to any valid
claim against either Party for a brokerage commission, finder's fee or other
like payment with respect to the transactions contemplated by this Agreement,
excluding, in the case of FNB, fees to be paid to The Robinson-Humphrey Company,
LLC, and in the case Promistar, fees to be paid to Keefe, Bruyette & Woods, in
each case pursuant to letter agreements which have been heretofore disclosed to
the other Party.

         11.4     Entire Agreement. Except as otherwise expressly provided
herein, this Agreement constitutes the entire agreement between the Parties with
respect to the transactions contemplated hereunder and supersedes all prior
arrangements or understandings with respect thereto, written or oral. Other than
as provided in Section 8.14, nothing in this Agreement expressed or implied, is
intended to confer upon any Person, other than the Parties or their respective
successors, any rights, remedies, obligations, or liabilities under or by reason
of this Agreement.

         11.5     Amendments. To the extent permitted by Law, this Agreement may
be amended by a subsequent writing signed by each of the Parties upon the
approval of the Board of Directors of each of the Parties, whether before or
after shareholder approval of this Agreement has been obtained; provided, that
after any such approval by the shareholders of a Party, there shall be made no
amendment that modifies in any material respect the consideration to be received
by holders of Promistar Common Stock without the further approval of such
shareholders.

         11.6     Obligations of FNB. Whenever this Agreement requires FNB or
Promistar to take any action, such requirement shall be deemed to include an
undertaking by such Party to cause the Subsidiaries of such Party to take such
action.

         11.7     Waivers.

         (a)      Prior to or at the Effective Time, FNB, acting through its
Board of Directors, chief executive officer, president, or other authorized
officer, shall have the right to waive any default in the performance of any
term of this Agreement by Promistar, to waive or extend the time for the
compliance or fulfillment by Promistar of any and all of its obligations under
this Agreement, and to waive any or all of the conditions precedent to the
obligations of FNB under this Agreement, except any condition which, if not
satisfied, would result in the violation of any Law. No such waiver shall be
effective unless in writing signed by a duly authorized officer of FNB.

         (b)      Prior to or at the Effective Time, Promistar, acting through
its Board of Directors, chief executive officer, president or other authorized
officer, shall have the right to waive any default in the performance of any
term of this Agreement by FNB, to waive or extend the time for the compliance or
fulfillment by FNB of any and all of its obligations under this Agreement, and
to waive any or all of the conditions precedent to the obligations of Promistar
under this Agreement, except any condition which, if not satisfied, would result
in the violation of any Law. No such waiver shall be effective unless in writing
signed by a duly authorized officer of Promistar.

         (c)      The failure of any Party at any time or times to require
performance of any provision hereof shall in no manner affect the right of such
Party at a later time to enforce the same or any other provision of this
Agreement. No waiver of any condition or of the breach of any term contained in
this Agreement in one or more instances shall be deemed to be or construed as a
further or continuing waiver of such condition or breach or a waiver of any
other condition or of the breach of any other term of this Agreement.


                                       46
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         11.8     Assignment. Except as expressly contemplated hereby, neither
this Agreement nor any of the rights, interests, or obligations hereunder shall
be assigned by any Party hereto (whether by operation of Law or otherwise)
without the prior written consent of the other Party. Subject to the preceding
sentence, this Agreement will be binding upon, inure to the benefit of, and be
enforceable by the Parties and their respective successors and assigns.

         11.9     Notices. All notices or other communications which are
required or permitted hereunder shall be in writing and sufficient if delivered
by hand, by facsimile transmission, by registered or certified mail, postage
pre-paid, or by courier or overnight carrier, to the persons at the addresses
set forth below (or at such other address as may be provided hereunder), and
shall be deemed to have been delivered as of the date so delivered:

                    
                  Promistar:             Promistar Financial Corporation
                                         551 Main Street
                                         P.O. Box 1146
                                         Johnstown, Pennsylvania 15901-1146
                                         Telecopy Number: 814-536-2278
                                         Attention: Chairman and Chief Executive Officer

                  Copy to Counsel:       Kirkpatrick & Lockhart LLP
                                         Henry W. Oliver Building
                                         535 Smithfield Street
                                         Pittsburgh, Pennsylvania 15222
                                         Telecopy Number: 412-355-6501
                                         Attention: Kristen L. Stewart, Esq.

                  FNB:                   F.N.B. Corporation
                                         F.N.B. Center
                                         2150 Goodlette Road North
                                         Naples, Florida 34102
                                         Telecopy Number: 941-435-7658
                                         Attention: President and Chief Executive Officer

                  Copy to Counsel:       Smith, Gambrell & Russell, LLP
                                         1230 Peachtree Road, NE
                                         Suite 3100, Promenade II
                                         Atlanta, Georgia 30309
                                         Telecopy Number: 404-685-7058
                                         Attention: Robert C. Schwartz, Esq.

                  

         11.10    Governing Law. This Agreement shall be governed by and
construed in accordance with the Laws of the State of Florida, without regard to
any applicable conflicts of Laws, except to the extent that the Laws of the
Commonwealth of Pennsylvania relate to the consummation of the Merger.

         11.11    Counterparts. This Agreement may be executed in two or more
counterparts, each of which shall be deemed to be an original, but all of which
together shall constitute one and the same instrument.

         11.12    Captions. The captions contained in this Agreement are for
reference purposes only and are not part of this Agreement.


                                       47
   53

         11.13    Enforcement of Agreement. The Parties hereto agree that
irreparable damage would occur in the event that any of the provisions of this
Agreement was not performed in accordance with its specific terms or was
otherwise breached. It is accordingly agreed that the Parties shall be entitled
to an injunction or injunctions to prevent breaches of this Agreement and to
enforce specifically the terms and provisions hereof in any court of the United
States or any state having jurisdiction, this being in addition to any other
remedy to which they are entitled at law or in equity.

         11.14    Severability. Any term or provision of this Agreement which is
invalid or unenforceable in any jurisdiction shall, as to that jurisdiction, be
ineffective to the extent of such invalidity or unenforceability without
rendering invalid or unenforceable the remaining terms and provisions of this
Agreement or affecting the validity or enforceability of any of the terms or
provisions of this Agreement in any other jurisdiction. If any provision of this
Agreement is so broad as to be unenforceable, the provision shall be interpreted
to be only so broad as is enforceable.

                [Remainder of this Page Intentionally Left Blank]


                                       48
   54

         IN WITNESS WHEREOF, each of the Parties has caused this Agreement to be
executed on its behalf by its duly authorized officer as of the day and year
first above written.

                                    F.N.B. CORPORATION


                           By:      /s/ Gary L. Tice
                                    --------------------------------------------
                                    Gary L. Tice
                                    President and Chief Executive Officer

                                    PROMISTAR FINANCIAL CORPORATION


                           By:      /s/ John H. Anderson
                                    --------------------------------------------
                                    John H. Anderson
                                    Chairman and Chief Executive Officer


                                       49

EX-10.1

   1
                                                                    EXHIBIT 10.1

                             STOCK OPTION AGREEMENT

         This STOCK OPTION AGREEMENT (this "Agreement") is entered into this
13th day of June, 2001, between F.N.B. CORPORATION, a Florida corporation
having its principal office located in Naples, Florida ("FNB"), and PROMISTAR
FINANCIAL CORPORATION, a Pennsylvania corporation having its principal office
located in Johnstown, Pennsylvania ("Promistar").

                                   WITNESSETH:

         WHEREAS, FNB and Promistar have entered into an Agreement and Plan of
Merger of even date herewith (the "Merger Agreement"), which agreement has been
executed by the parties hereto prior to the execution of this Agreement; and

         WHEREAS, as a condition and inducement to FNB's pursuit of the
transactions contemplated by the Merger Agreement and in consideration therefor,
Promistar has agreed to grant FNB the Option (as hereinafter defined).

         NOW, THEREFORE, in consideration of the foregoing and the mutual
covenants and agreements set forth herein and in the Merger Agreement, the
parties hereto agree as follows:

         1.  (a) Promistar hereby grants to FNB an irrevocable option (the
"Option") to purchase, subject to the terms hereof, up to 2,975,830 authorized
but unissued fully paid and nonassessable Common Shares, $5.00 par value, of
Promistar ("Common Shares"), at a price per Common Share equal to $17.306 (as
adjusted as set forth herein, the "Option Price"); provided, that in no event
shall the number of Common Shares for which this Option is exercisable, when
combined with the Promistar Common Shares beneficially owned at such time by
FNB, exceed 19.9% of the issued and outstanding Common Shares. The number of
Common Shares that may be received upon the exercise of the Option and the
Option Price are subject to adjustment as herein set forth.

              (b) In the event that any additional Common Shares are issued or
otherwise become outstanding after the date of this Agreement (other than
pursuant to this Agreement), the number of Common Shares subject to the Option
shall be increased so that, after such issuance, it equals 19.9% of the number
of Common Shares then issued and outstanding including Common Shares
beneficially owned by FNB, but without giving effect to any Shares subject or
issued pursuant to the Option. Nothing contained in this Section 1(b) or
elsewhere in this Agreement shall be deemed to authorize Promistar or FNB to
breach any provision of the Merger Agreement.

         2.   (a) Subject to compliance with applicable laws and regulations,
the Holder (as hereinafter defined) may exercise the Option, notwithstanding the
provisions of the Confidentiality Agreements (as defined in the Merger
Agreement) in whole or part, if, but only if, both an Initial Triggering Event
(as hereinafter defined) and a Subsequent Triggering Event (as hereinafter
defined) shall have occurred prior to the occurrence of an Exercise Termination
Event (as hereinafter defined). Each of the following shall be an Exercise
Termination Event: (i) the Effective Time (as defined in the Merger Agreement)
of the Merger; (ii) termination of the Merger Agreement in accordance with the
provisions thereof if such termination occurs prior to the occurrence of an
Initial Triggering Event (other than termination due to


                                       1

   2


the failure of FNB to satisfy a condition to closing; (iii) the passage of 12
months (or such longer period as provided in Section 9) after termination of the
Merger Agreement if such termination follows the occurrence of an Initial
Triggering Event; or (iv) such other date as to which the Holder and Promistar
agree. The term "Holder" shall mean the holder or holders of the Option. The
rights set forth in Section 7 shall terminate when the right to exercise the
Option terminates (other than as a result of a complete exercise of the Option)
as set forth herein.

              (b) The term "Initial Triggering Event" shall mean any of the
following events or transactions occurring after the date hereof:

                  (i)     Promistar or any of its Subsidiaries (as hereinafter
defined) (each a "Promistar Subsidiary"), without having received FNB's prior
written consent, shall have entered into an agreement to engage in an
Acquisition Transaction (as hereinafter defined) with any person (the term
"person" for purposes of this Agreement having the meaning assigned thereto in
Sections 3(a)(9) and 13(d)(3) of the Securities Exchange Act of 1934 (the "1934
Act"), and the rules and regulations thereunder) other than FNB or any of its
Subsidiaries (each a "FNB Subsidiary") or the Board of Directors of Promistar
shall have recommended that the shareholders of Promistar approve or accept any
Acquisition Transaction other than as contemplated by the Merger Agreement or
this Agreement. For purposes of this Agreement, (a) "Acquisition Transaction"
shall mean (x) a merger or consolidation, or any similar transaction, involving
Promistar or any Significant Subsidiary (as defined in Rule 1-02 of Regulation
S-X promulgated by the Securities and Exchange Commission (the "SEC")) of
Promistar, (y) a purchase, lease or other acquisition of all or substantially
all of the assets or deposits of Promistar or any Significant Subsidiary of
Promistar, or (z) a purchase or other acquisition (including by way of merger,
consolidation, share exchange or otherwise) of securities representing 15% or
more of the voting power of Promistar or any Significant Subsidiary of
Promistar, and (b) "Subsidiary" shall have the meaning set forth in Rule 12b-2
under the 1934 Act;

                  (ii)    Any person (excluding the officers and directors of
Promistar) other than FNB, any FNB Subsidiary or any Promistar Subsidiary acting
in a fiduciary capacity shall have acquired beneficial ownership or the right to
acquire beneficial ownership of 15% or more of the outstanding Common Shares
(the term "beneficial ownership" for purposes of this Agreement having the
meaning assigned thereto in Section 13(d) of the 1934 Act, and the rules and
regulations thereunder);

                  (iii)   The shareholders of the Promistar shall not have
approved the transactions contemplated by the Merger Agreement at the meeting
held for that purpose or any adjustment thereof, or such meeting shall not have
been held or shall have been canceled prior to termination of the Merger
Agreement, in either case, after Promistar's Board of Directors shall have
withdrawn or modified (or publicly announced its intention to withdraw or modify
or interest in withdrawing or modifying) its recommendation that the
shareholders of Promistar approve the transactions contemplated by the Merger
Agreement, or Promistar or any Promistar Subsidiary, without having received
FNB's prior written consent, shall have authorized, recommended, proposed (or
publicly announced its intention to authorize, recommend or propose or interest
in authorizing, recommending or proposing) an agreement to engage in an
Acquisition Transaction, with any person other than FNB or a FNB Subsidiary;

                  (iv)    Any person other than FNB or any FNB Subsidiary shall
have made a bona fide proposal to Promistar or its shareholders to engage in an
Acquisition Transaction, which proposal has an economic value equivalent to or
in excess of that of FNB.


                                       2

   3


                  (v)   Promistar shall have willfully and materially breached
any material covenant or obligation contained in the Merger Agreement in
anticipation of engaging in an Acquisition Transaction, and such breach would
entitle FNB to terminate the Merger Agreement; or

                  (vi)  Any person other than FNB or any FNB Subsidiary, other
than in connection with a transaction to which FNB has given its prior written
consent, shall have filed an application or notice with the Federal Reserve
Board or other federal or state bank regulatory authority, which application or
notice has been accepted for processing, for approval to engage in an
Acquisition Transaction.

              (c) The term "Subsequent Triggering Event" shall mean any of the
following events or transactions occurring after the date hereof:

                  (i)  The acquisition by any person of beneficial ownership of
25% or more of the then outstanding Common Shares; or

                  (ii) The occurrence of the Initial Triggering Event described
in clause (i) of subsection (b) of this Section 2, except that the percentage
referred to in clause (z) shall be 25%.

              (d) Promistar shall notify FNB promptly in writing of the
occurrence of any Initial Triggering Event or Subsequent Triggering Event
(together, a "Triggering Event"), it being understood that the giving of such
notice by Promistar shall not be a condition to the right of the Holder to
exercise the Option.

              (e) No shares shall be issued pursuant to the exercise of this
Option if (i) at the time of the Initial Triggering Event and at the time of
exercise, FNB is in material breach under the Merger Agreement, or (ii) a
preliminary or permanent injunction has been issued by a court of proper
jurisdiction with respect to this Option or the Merger Agreement or the
transactions contemplated hereby or thereby.

              (f) In the event the Holder is entitled to and wishes to exercise
the Option, it shall send to Promistar a written notice prior to an Exercise
Termination Event (the date of which being herein referred to as the "Notice
Date") specifying (i) the total number of shares it will purchase pursuant to
such exercise and (ii) a place and date not earlier than three business days nor
later than 10 business days from the Notice Date for the closing of such
purchase (the "Closing Date"); provided that if prior notification to or
approval of the Federal Reserve Board or any other regulatory agency is required
in connection with such purchase, the Holder shall promptly file the required
notice or application for approval, shall promptly notify the Promistar of such
filing, and shall expeditiously process the same and the period of time that
otherwise would run pursuant to this sentence shall run instead from the date on
which any required notification periods have expired or been terminated or such
approvals have been obtained and any requisite waiting period or periods shall
have passed. Any exercise of the Option shall be deemed to occur on the Notice
Date relating thereto.

              (g) At the closing referred to in subsection (e) of this Section
2, the Holder shall pay to Promistar the aggregate purchase price for the Common
Shares purchased pursuant to the exercise of the Option in immediately available
funds by wire transfer to a bank account designated by Promistar, provided that
failure or refusal of Promistar to designate such a bank account shall not
preclude the Holder from exercising the Option.


                                       3


   4

              (h) At such closing, simultaneously with the delivery of
immediately available funds as provided in subsection (f) of this Section 2,
Promistar shall deliver to the Holder a certificate or certificates representing
the number of Common Shares purchased by the Holder and, if the Option should be
exercised in part only, a new Option evidencing the rights of the Holder thereof
to purchase the balance of the shares purchasable thereunder. In addition, the
Holder shall provide to Promistar a letter agreeing that Holder will not offer
to sell or dispose of such shares in violation of applicable law or this
Agreement

              (i) Certificates for Common Shares delivered at a closing
hereunder may be endorsed with a restrictive legend that shall read
substantially as follows:

                  "The transfer of the shares represented by this certificate is
                  subject to certain provisions of an agreement between the
                  registered holder hereof and Promistar and to resale
                  restrictions arising under the Securities Act of 1933, as
                  amended. A copy of such agreement is on file at the principal
                  office of Promistar and will be provided to the holder hereof
                  without charge upon receipt by Promistar of a written request
                  therefor."

                  It is understood and agreed that: (1) the reference to the
                  resale restrictions of the Securities Act of 1933 (the "1933
                  Act") in the above legend shall be removed by delivery of
                  substitute certificate(s) without such reference if the Holder
                  shall have delivered to Promistar a copy of a letter from the
                  staff of the SEC, or an opinion of counsel, in form and
                  substance satisfactory to Promistar, to the effect that such
                  legend is not required for purposes of the 1933 Act; (ii) the
                  reference to the provisions of this Agreement in the above
                  legend shall be removed by delivery of substitute
                  certificate(s) without such reference if the shares have been
                  sold or transferred in compliance with the provisions of this
                  Agreement and under circumstances that do not require the
                  retention of such reference; and (iii) the legend shall be
                  removed in its entirety if the conditions in the proceeding
                  clauses (i) and (ii) are both satisfied. In addition, such
                  certificates shall bear any other legend as may be required by
                  law.

              (j) Upon the giving by the Holder to Promistar of the written
notice of exercise of the Option provided for under subsection (e) of this
Section 2 and the tender of the applicable purchase price in immediately
available funds the Holder shall be deemed to be the holder of record of the
Common Shares issuable upon such exercise, notwithstanding that the stock
transfer books of Promistar shall then be closed or that certificates
representing such Common Shares shall not then be actually delivered to the
Holder. Promistar shall pay all expenses, and any and all United States federal,
state and local taxes and other charges that may be payable in connection with
the preparation, issue and delivery of stock certificates under this Section 2
in the name of the Holder or its assignee, transferee or designee.

         3. Promistar agrees: (a) that it shall at all times maintain, free from
preemptive rights, sufficient authorized but unissued or treasury shares of
Common Shares so that the Option may be exercised without additional
authorization of Common Shares after giving effect to all other options,
warrants, convertible securities and other rights to purchase Common Shares; (b)
that it will not, by charter amendment or through reorganization, consolidation,
merger, dissolution or sale of assets, or by any other voluntary act, avoid or
seek to avoid the observance or performance of any of the covenants,
stipulations


                                       4


   5

or conditions to be observed or performed hereunder by Promistar; (c) promptly
to take all action as may from time to time be required (including (i) complying
with all premerger notification, reporting and waiting period requirements
specified in 15 U.S.C. Section 18a and regulations promulgated thereunder and
(ii) in the event, under the Bank Holding Company Act of 1956, as amended, or
any state or other federal banking law, prior approval of or notice to the
Federal Reserve Board or to any state or other federal regulatory authority is
necessary before the Option may be exercised, cooperating fully with the Holder
in preparing such applications or notices and providing such information to the
Federal Reserve Board or such state or other federal regulatory authority as
they may require) in order to permit the Holder to exercise the Option and
Promistar duly and effectively to issue Common Shares pursuant hereto; and (d)
promptly to take all action provided herein to protect the rights of the Holder
against dilution as set forth in Section 5 hereof.

         4. This Agreement (and the Option granted hereby) are exchangeable,
without expense, at the option of the Holder, upon presentation and surrender of
this Agreement at the principal office of Promistar, for other Agreements
providing for Options of different denominations entitling the holder thereof to
purchase, on the same terms and subject to the same conditions as are set forth
herein, in the aggregate the same number of Common Shares purchasable hereunder.
The terms "Agreement" and "Option" as used herein include any Agreements and
related Options for which this Agreement (and the Option granted hereby) may be
exchanged. Upon receipt by Promistar of evidence reasonably satisfactory to it
of the loss, theft, destruction or mutilation of this Agreement, and (in the
case of loss, theft or destruction) of reasonably satisfactory indemnification,
and upon surrender and cancellation of this Agreement, if mutilated, Promistar
will execute and deliver a new Agreement of like tenor and date.

         5. The number of Common Shares purchasable upon the exercise of the
Option shall be subject to adjustment from time to time as provided in this
Section 5.

            (a) In the event of any change in Common Shares by reason of stock
dividends, splitups, mergers, recapitalizations, combinations, subdivisions,
conversions, exchanges of shares or the like, the type and number of Common
Shares purchasable upon exercise hereof shall be appropriately adjusted and
proper provision shall be made so that, in the event that any additional Common
Shares are to be issued or otherwise become outstanding as a result of any such
change (other than pursuant to an exercise of the Option), the number of Common
Shares that remain subject to the Option shall be increased so that, after such
issuance and together with Common Shares previously issued pursuant to the
exercise of the Option (together with the number of Shares previously issued
under this Option and the number of Shares otherwise beneficially owned by FNB)
(as adjusted on account of any of the foregoing changes in the Common Shares),
it equals 19.9% of the number of Common Shares then issued and outstanding.

            (b) Whenever the number of Common Shares purchasable upon exercise
hereof is adjusted as provided in this Section 5, the Option Price shall be
adjusted by multiplying the Option Price by a fraction, the numerator of which
shall be equal to the number of Common Shares purchasable prior to the
adjustment and the denominator of which shall be equal to the number of Common
Shares purchasable after the adjustment.

         6. Upon the occurrence of a Subsequent Triggering Event that occurs
prior to an Exercise Termination Event, Promistar shall, at the request of FNB
delivered prior to an Exercise Termination Event (or such later period as
provided in Section 9) (whether on its own behalf or on behalf of any subsequent
holder of this Option (or part thereof) or any of the Common Shares issued
pursuant hereto), promptly prepare, file and keep current a registration
statement under the 1933 Act covering any shares


                                       5


   6


issued and issuable pursuant to this Option and shall use its best efforts to
cause such registration statement to become effective and remain current in
order to permit the sale or other disposition of any Common Shares issued upon
total or partial exercise of this Option ("Option Shares") in accordance with
any plan of disposition requested by FNB. Promistar will use its best efforts to
cause such registration statement first to become effective and then to remain
effective for such period not in excess of 120 days from the day such
registration statement first becomes effective or such shorter time as may be
reasonably necessary to effect such sales or other dispositions. FNB shall have
the right to demand two such registrations. The first demand registration
effected under this Section 6 shall be at Promistar's expense except for
underwriting commissions and the fees and expenses of FNB's counsel attributable
to the registration of the Common Shares. The second demand registration shall
be at FNB's expense. In addition, if at any time after the occurrence of a
Subsequent Triggering Event that occurs prior to an Exercise Termination Event,
Promistar proposes to register any of its equity securities under the 1933 Act,
whether for sale for its own account or for the account of any other person, on
a form and in a manner which would permit registration of the Common Shares
issued pursuant hereto for sale to the public under the 1933 Act, it will each
such time give prompt written notice to FNB of its intention to do so,
describing such securities and specifying the form and manner and the other
relevant facts involved in such proposed registration, and upon the written
request of FNB delivered to the Company within 10 business days after the giving
of any such notice (which request shall specify the Common Shares intended to be
disposed of and the intended method or methods of disposition thereof),
Promistar will use its best efforts to effect the registration under the 1933
Act of all Common Shares which Promistar has been so requested to register by
FNB, to the extent requisite to permit the disposition of the Common Shares in
accordance with the intended methods thereof as specified by FNB. Promistar
shall be obligated to effect only one such piggy-back registration pursuant to
this Section 6. FNB shall pay such incremental expenses incurred by Promistar in
connection with registering the Common Shares requested to be registered by FNB
pursuant to its piggy-back registration rights under this Section 6, which
expenses are in addition to the expenses that Promistar would have otherwise
incurred in registering equity securities under the 1933 Act. The foregoing
notwithstanding, if, at the time of any request by FNB for registration of
Option Shares as provided above, Promistar has initiated discussions with
investment bankers concerning, or is in registration with respect to an
underwritten public offering of Common Shares, and if in the good faith judgment
of the managing underwriter or managing underwriters, or, if none, the sole
underwriter or underwriters, of such offering the inclusion of the Option Shares
would interfere with the successful marketing of the Common Shares offered by
Promistar, the number of Option Shares otherwise to be covered in the
registration statement contemplated hereby may be reduced; provided, however,
that after any such required reduction the number of Option Shares to be
included in such offering for the account of the Holder shall constitute at
least 25% of the total number of shares to be sold by the Holder and Promistar
in the aggregate; and provided further, however, that if such reduction occurs,
then the Promistar shall file a registration statement for the balance as
promptly as practical thereafter as to which no reduction pursuant to this
Section 6 shall be permitted or occur and the Holder shall thereafter be
entitled to one additional registration at Holder's expense. Each such Holder
shall provide all information reasonably requested by Promistar for inclusion in
any registration statement to be filed hereunder. If requested by any such
Holder in connection with such registration, Promistar shall become a party to
any underwriting agreement relating to the sale of such shares, but only to the
extent of obligating itself in respect of representations, warranties,
indemnities and other agreements customarily included in such underwriting
agreements for Promistar. In any such registration, Promistar and FNB shall
agree to indemnify each other on customary terms with regard to any information
provided by such party. Upon receiving any request under this Section 6 from any
Holder, Promistar agrees to send a copy thereof to any other person known to
Promistar to be entitled to registration rights under this Section 6, in each
case by promptly mailing the same, postage prepaid, to the address of record of
the persons entitled to receive such copies.


                                       6


   7


         7. (a) Upon the occurrence of a Repurchase Event (as hereinafter
defined) that occurs prior to an Exercise Termination Event, (i) at the request
of the Holder, delivered prior to an Exercise Termination Event (or such later
period as provided in Section 9), Promistar shall repurchase the Option from the
Holder at a price (the "Option Repurchase Price") equal to the amount by which
(A) the Market/Offer Price (as defined below) exceeds (B) the Option Price,
multiplied by the number of shares for which this Option may then be exercised
and (ii) at the request of the owner of Option Shares from time to time (the
"Owner"), delivered prior to the occurrence of an Exercise Termination Event (or
such later period as provided in Section 9), Promistar shall repurchase such
number of the Option Shares from the Owner as the Owner shall designate at a
price (the "Option Share Repurchase Price") equal to the Market/Offer Price
multiplied by the number of Option Shares so designated. The term "Repurchase
Event" shall occur if (i) any person other than FNB or any of its Subsidiaries
shall have acquired beneficial ownership, or the right to acquire beneficial
ownership, or any "group" (as such term is defined under the 1934 Act) shall
have been formed which beneficially owns or has the right to acquire beneficial
ownership of 50% or more of the then-outstanding Common Shares, or (ii) any of
the transactions described in Section 8(a)(i), 8(a)(ii), or 8(a)(iii) hereof
shall be consummated. The term "Market/Offer Price" shall mean the highest of
(i) the price per share of Common Shares at which a tender or exchange offer
therefor has been made, (ii) the price per share of Common Shares to be paid by
any third party pursuant to an agreement with Promistar, (iii) the highest
closing price for Common Shares within the three-month period immediately
preceding the date the Holder gives notice of the required repurchase of this
Option or the Owner gives notice of the required repurchase of Option Shares, as
the case may be, or (iv) in the event of a sale of all or substantially all of
Promistar's assets or deposits, the sum of the net price paid in such sale for
such assets or deposits, the sum of the net price paid in such sale for such
assets or deposits and the current market value of the remaining net assets of
Promistar as determined by a nationally recognized investment banking firm
selected by the Holder or the Owner, as the case may be, divided by the number
of Common Shares of Promistar outstanding at the time of such sale. In
determining the Market/Offer Price, the value of consideration other than cash
shall be determined by a nationally recognized investment banking firm selected
by the Holder or Owner, as the case may be.

              (b) The Holder and the Owner, as the case may be, may exercise its
right to require Promistar to repurchase the Option and any Option Shares
pursuant to this Section 7 by surrendering for such purpose to Promistar, at its
principal office, a copy of this Agreement or certificates for Option Shares, as
applicable, accompanied by a written notice or notices stating that the Holder
or the Owner, as the case may be, elects to require Promistar to repurchase this
Option and/or the Option Shares in accordance with the provisions of this
Section 7. As promptly as practicable, and in any event within ten business days
after the surrender of the Option and/or certificates representing Option Shares
and the receipt of such notice or notices relating thereto, Promistar shall
deliver or cause to be delivered to the Holder the Option Repurchase Price
and/or to the Owner the Option Share Repurchase Price therefor or the portion
thereof that Promistar is not then prohibited under applicable law and
regulation from so delivering.

              (c) To the extent that Promistar is prohibited under applicable
law or regulation, or as a consequence of administrative policy, from
repurchasing the Option and/or the Option Shares in full, Promistar shall
immediately so notify the Holder and/or the Owner and thereafter deliver or
cause to be delivered, from time to time, to the Holder and/or the Owner, as
appropriate, the portion of the Option Repurchase Price and the Option Share
Repurchase Price, respectively, that it is no longer prohibited from delivering,
within ten business days after the date on which Promistar is no longer so
prohibited; provided, however, that if Promistar at any time after delivery of a
notice of repurchase pursuant to


                                       7

   8


paragraph (b) of this Section 7 is prohibited under applicable law or
regulation, or as a consequence of administrative policy, from delivery to the
Holder and/or the Owner, as appropriate, the Option Repurchase Price and the
Option Share Repurchase Price, respectively, in full (and Promistar hereby
undertakes to use its best efforts to obtain all required regulatory and legal
approvals and to file any required notices as promptly as practicable in order
to accomplish such repurchase), the Holder or Owner may revoke its notice of
repurchase of the Option or the Option Shares whether in whole or to the extent
of the prohibition, whereupon, in the latter case, Promistar shall promptly (i)
deliver to the Holder and/or the Owner, as appropriate, that portion of the
Option Purchase Price or the Option Share Repurchase Price that Promistar is not
prohibited from delivering, and (ii) deliver, as appropriate, either (A) to the
Holder, a new Agreement evidencing the right of the Holder to purchase that
number of Common Shares obtained by multiplying the number of Common Shares for
which the surrendered Agreement was exercisable at the time of delivery of the
notice of repurchase by a fraction, the numerator of which is the Option
Repurchase Price less the portion thereof theretofore delivered to the Holder
and the denominator of which is the Option Repurchase Price, or (B) to the
Owner, a certificate for the Option Shares it is then so prohibited from
repurchasing.

         8. (a) In the event that, prior to an Exercise Termination Event,
Promistar shall enter into an agreement (i) to consolidate with or merge into
any person, other than FNB or a FNB Subsidiary, and shall not be the continuing
or surviving corporation of such consolidation or merger, (ii) to permit any
person, other than FNB or a FNB Subsidiary, to merge into Promistar and
Promistar shall be the continuing or surviving corporation, but, in connection
with such merger, the then outstanding Common Shares shall be changed into or
exchanged for stock or other securities of any other person or cash or any other
property or the then outstanding Common Shares shall after such merger represent
less than 50% of the outstanding shares and share equivalents of the merged
company, or (iii) to sell or otherwise transfer all or substantially all of its
or any Significant Subsidiary's assets or deposits to any person, other than FNB
or a FNB Subsidiary, then, and in each such case, the agreement governing such
transaction shall make proper provision so that the Option shall, upon the
consummation of any such transaction and upon the terms and conditions set forth
herein, be converted into, or exchanged for, an option (the "Substitute
Option"), at the election of the Holder, of either (x) the Acquiring Corporation
(as hereinafter defined) or (y) any person that controls the Acquiring
Corporation.

            (b) The following terms have the meanings indicated:

                (i)    "Acquiring Corporation" shall mean (i) the continuing or
surviving corporation of a consolidation or merger with Promistar (if other than
Promistar), (ii) Promistar in a merger in which Promistar is the continuing or
surviving person, and (iii) the transferee of all or substantially all of
Promistar's assets or deposits (or the assets or deposits of a Significant
Subsidiary of Promistar).

                (ii)   "Substitute Common Shares" shall mean the common shares
issued by the issuer of the Substitute Option upon exercise of the Substitute
Option.

                (iii)  "Assigned Value" shall mean the Market/Offer Price, as
defined in Section 7.

                (iv)   "Average Price" shall mean the average closing price of
the Substitute Common Share for the one year immediately preceding the
consolidation, merger or sale in question, but in no event higher than the
closing price of the substitute Common Shares on the day preceding such
consolidation, merger or sale; provided that if Promistar is the issuer of the
Substitute Option, the Average Price shall be computed with respect to common
shares issued by the person merging into Promistar or by any company which
controls or is controlled by such person, as the Holder may elect.


                                       8

   9


              (c) The Substitute Option shall have the same terms as the Option,
provided, that if the terms of the Substitute Option cannot, for legal reasons,
be the same as the Option, such terms shall be as similar as possible and in no
event less advantageous to the Holder. The issuer of the Substitute Option shall
also enter into an agreement with the then Holder or Holders of the Substitute
Option in substantially the same form as this Agreement, which agreement shall
be applicable to the Substitute Option.

              (d) The Substitute Option shall be exercisable for such number of
Substitute Common Shares as is equal to the Assigned Value multiplied by the
number of Common Shares for which the Option is then exercisable, divided by the
Average Price. The exercise price of the Substitute Option per Substitute Common
Share shall then be equal to the Option Price multiplied by a fraction, the
numerator of which shall be the number of Common Shares for which the Option is
then exercisable and the denominator of which shall be the number of Substitute
Common Shares for which the Substitute Option is exercisable.

              (e) In no event, pursuant to any of the foregoing paragraphs,
shall the Substitute Option be exercisable for a number of shares which together
with shares of the Acquiring Corporation then beneficially owned by FNB,
constitutes more than 19.9% of the shares of Substitute Common Shares
outstanding prior to exercise of the Substitute Option.

         9.   The periods for exercise of certain rights under Sections 2, 6,
and 7 shall be extended: (i) to the extent necessary to obtain all regulatory
approvals for the exercise of such rights (for so long as the Holder is using
commercially reasonable efforts to obtain such regulatory approvals), and for
the expiration of all statutory waiting periods; and (ii) to the extent
necessary to avoid liability under Section 16(b) of the 1934 Act by reason or
such exercise.

         10.  Promistar hereby represents and warrants to FNB as follows:

              (a) Promistar has full corporate power and authority to execute
and deliver this Agreement and to consummate the transactions contemplated
hereby. The execution and delivery this Agreement and the consummation of the
transactions contemplated hereby have been duly and validly authorized by the
Board of Directors of Promistar and no other corporate proceedings on the part
of Promistar are necessary to authorize this Agreement or to consummate the
transactions so contemplated. This Agreement has been duly and validly executed
and delivered by Promistar.

              (b) Promistar has taken all necessary corporate action to
authorize and reserve and to permit it to issue, and at all times from the date
hereof through the termination of this Agreement in accordance with its terms
will have reserved for issuance upon the exercise of the Option, that number of
Common Shares equal to the maximum number of Common Shares at any time and from
time to time issuable hereunder, and all such shares, upon issuance pursuant
thereto, will be duly authorized, validly issued, fully paid, nonassessable.

         11.  Neither of the parties hereto may assign any of its rights or
obligations under this Agreement or the Option created hereunder to any other
person, without the express written consent of the other party, except that in
the event a Subsequent Triggering Event shall have occurred prior to an Exercise
Termination Event, FNB, subject to the express provisions hereof, may assign in
whole or in part its rights and obligations hereunder following such Subsequent
Triggering Event; provided, however that


                                       9


   10


until the date 30 days following the date on which the Federal Reserve Board has
approved applications by FNB to acquire the Common Shares subject to the Option,
FNB may not assign its rights under the Option except in (i) a widely dispersed
public distribution, (ii) a private placement in which no one party acquires the
right to purchase in excess of 2% of the voting shares of issuer, (iii) an
assignment to a single party (i.e., a broker or investment banker) for the
purpose of conducting a widely disbursed public distribution on FNB's behalf, or
(iv) any other manner approved by the Federal Reserve Board.

         12.  Each of FNB and Promistar will use its best efforts to make all
filings with, and to obtain consents of, all third parties and governmental
authorities necessary to the consummation of the transactions contemplated by
this Agreement, including without limitation applying to the Federal Reserve
Board under the Bank Holding Company Act for approval to acquire the shares
issuable hereunder, but FNB shall not be obligated to apply to state banking
authorities for approval to acquire the Common Shares issuable hereunder until
such time, if ever, as it deems appropriate to do so.

         13.  The parties hereto acknowledge that damages would be an inadequate
remedy for a breach of this Agreement by either party hereto and that the
obligations of the parties hereto shall be enforceable by either party hereto
through injunctive or other equitable relief.

         14.  If any term, provision, covenant or restriction contained in this
Agreement is held by a court or a federal or state regulatory agency of
competent jurisdiction to be invalid, void or unenforceable, the remainder of
the terms, provisions and covenants and restrictions contained in this Agreement
shall remain in full force and effect, and shall in no way be affected, impaired
or invalidated. If for any reason such court or regulatory agency determines
that the Holder is not permitted to acquire, or Promistar is not permitted to
repurchase pursuant to Section 7, the full number of Common Shares provided in
Section 1(a) hereof (as adjusted pursuant to Section 5 hereof), it is the
express intention of Promistar to allow the Holder to acquire or to require
Promistar to repurchase such lesser number of shares as may be permissible,
without any amendment or modification hereof.

         15.  All notices, requests, claims, demands and other communications
hereunder shall be deemed to have been duly given when delivered in person, by
fax, telecopy, or by registered or certified mail (postage prepaid, return
receipt requested) at the respective addresses of the parties set forth in the
Merger Agreement.

         16.  This Agreement shall be governed by and construed in accordance
with the laws of the State of Florida, regardless of the laws that might
otherwise govern under applicable principles of conflicts of laws thereof.

         17.  This Agreement may be executed in two or more counterparts, each
of which shall be deemed to be an original, but all of which shall constitute
one and the same agreement.

         18.  Except as otherwise expressly provided herein, each of the parties
hereto shall bear and pay all costs and expenses incurred by it or on its behalf
in connection with the transactions contemplated hereunder, including fees and
expenses of its own financial consultants, investment bankers, accountants and
counsel.

         19.  Except as otherwise expressly provided herein or in the Merger
Agreement, this Agreement contains the entire agreement between the parties with
respect to the transactions contemplated hereunder and supersedes all prior
arrangements or understandings with respect thereof, written or oral. The terms


                                       10


   11

and conditions of this Agreement shall inure to the benefit of and be binding
upon the parties hereto and their respective successors and permitted assignees.
Nothing in this Agreement, expressed or implied, is intended to confer upon any
party, other than the parties hereto, and their respective successors except as
assignees, any rights, remedies, obligations or liabilities under or by reason
of this Agreement, except as expressly provided herein.

         20.  Capitalized terms used in this Agreement and not defined herein
shall have the meanings assigned thereto in the Merger Agreement.


                                       11


   12


         IN WITNESS WHEREOF, each of the parties hereto has caused this
Agreement to be executed on its behalf by its officer thereunto duly authorized,
all as of the date first above written.


                                      F.N.B. CORPORATION


                                  By: /s/ Gary L. Tice
                                      ------------------------------------------
                                      Gary L. Tice
                                      President and Chief Executive Officer


                                      PROMISTAR FINANCIAL CORPORATION


                                  By: /s/ John H. Anderson
                                      ------------------------------------------
                                      John H. Anderson
                                      Chairman and Chief Executive Officer


                                       12

EX-99.1

   1
                                                                    EXHIBIT 99.1


Joint FNB/Promistar Press Release dated June 14, 2001


   2

F.N.B. CORPORATION                               PROMISTAR FINANCIAL CORPORATION
(NASDAQ: FBAN)                                                    (NASDAQ: PRFC)
NAPLES, FL                                                        JOHNSTOWN, PA
WWW.FNBCORPORATION.COM                                        WWW.PROMISTAR.COM

FOR IMMEDIATE RELEASE

DATE:     June 14, 2001
CONTACT:  Clay W. Cone
          Vice President-Corporate Affairs
          724-983-3428


            F.N.B. CORPORATION & PROMISTAR FINANCIAL ANNOUNCE MERGER

NAPLES, FL., and JOHNSTOWN, PA., June 14 - F.N.B. Corporation (Nasdaq: FBAN) and
Promistar Financial Corporation (Nasdaq: PRFC) today announced the signing of a
definitive agreement in which Promistar will merge into F.N.B. This transaction
is expected to be accretive to F.N.B.'s earnings by more than 4% in 2002 and 5%
in 2003.

Under the terms of the definitive agreement, F.N.B. will exchange 0.926 shares
of its common stock for each share of Promistar common stock. Based on F.N.B.'s
June 13 closing price of $26.74 per share, the transaction is valued at
approximately $427 million.

Due diligence on the transaction has been completed by both parties and
completion of the transaction is subject to the normal regulatory approvals as
well as the approval of F.N.B. and Promistar shareholders. The transaction is
scheduled for completion in the first quarter of 2002 and is expected to be
accounted for as a pooling of interests.

Management expects the combined company to achieve synergies of 18% of
Promistar's non-interest expenses in 2002. On a fully phased-in basis, these
synergies are projected to increase to approximately 25%.

The combined company expects to incur one-time, merger-related charges of
approximately $41 million, on a pre-tax basis, during 2002 related to staff
retention and severance, systems integration, professional fees, investment
portfolio restructuring, fixed asset disposals, and other miscellaneous items.




   3



The combined company, headquartered in Naples, Florida, will have more than $6.5
billion in assets, $5.2 billion in deposits and 168 banking offices located in
southwest Florida, western Pennsylvania and northeastern Ohio. F.N.B. is the
largest independent bank holding company headquartered in Florida. As a result
of this merger, F.N.B. will become the eighth largest bank holding company,
based on total deposits, operating in the state of Pennsylvania and the 65th
largest bank holding company in the United States.

"This is a unique opportunity to merge with an organization that shares a
similar culture and heritage," said Gary L. Tice, President and Chief Executive
Officer of F.N.B. Corporation. "Promistar is a strong and successful community
banking organization that we've long admired. The combination of F.N.B. and
Promistar will create a franchise that we believe will be the premier financial
institution serving western Pennsylvania."

Promistar Bank currently operates 72 branches and will add another 10 locations
upon the completion of its previously announced merger with First National Bank
of Herminie in Herminie, Pennsylvania. F.N.B. currently operates 43 branches in
western Pennsylvania. Once the merger is completed, all Promistar offices will
operate under the First National Bank of Pennsylvania name. At least eight
branch offices are expected to be consolidated.

"We are excited about the opportunity to team up with F.N.B." said John H.
Anderson, Chairman and Chief Executive Officer of Promistar Financial
Corporation. "Both our employees and customers will be well served by F.N.B.'s
long-standing practice of operating with local decision-makers, local employees
and local Boards of Directors."

"This affiliation nearly triples the number of First National Bank offices and
adds approximately 1.4 million households to the bank's market area," said Steve
Gurgovits, President and Chief Executive Officer of First National Bank of
Pennsylvania. "We are pleased to be able to offer many new financial services
such as life insurance, property and casualty insurance, title insurance and
home mortgage lending. These services will be offered under our traditional
community banking style that we call Personal Banking."

Steven C. Ackmann, who currently serves as President and Chief Operating Officer
of Promistar, will join First National Bank of Pennsylvania as Senior Executive
Vice President and Chief Operating Officer. "I look forward to working with
F.N.B. as we combine these two fine community banking organizations into what we
believe will become the bank of choice for the citizens of western
Pennsylvania," he said.

F.N.B. Corporation is a diversified financial services company with more than
$4.1 billion in total assets. The company currently owns and operates
traditional community banks, insurance agencies, a consumer finance company and
First National Trust Company with offices located in Florida, Pennsylvania, Ohio
and Tennessee. The


   4



company has increased cash dividends for 29 consecutive years and has been
recognized as a Dividend Achiever by Mergent FIS, formerly known as Moody's
Investors Service.

Promistar, headquartered in Johnstown, Pennsylvania, is a bank holding company
with assets totaling $2.4 billion. Promistar's lead banking affiliate is
Promistar Bank, which serves 12 counties throughout southwestern Pennsylvania.
Other affiliates include Promistar Trust Company, a state-chartered trust
company; Promistar Investment Advisors Inc., a registered investment advisor;
Promistar Community Development Corporation, which provides housing for low- to
moderate-income citizens; Bedford Associates Inc., a real estate company; and
Flex Financial Consumer Discount Company.

F.N.B. and Promistar will host a conference call to discuss the transaction at
10:00 a.m. (Eastern Daylight Time) on June 14. Investors, analysts and other
interested parties may dial into the conference call at 1-800-388-8975. In
addition, a live webcast and slide presentation containing information related
to the transaction can be accessed and will be archived on F.N.B.'s web site at
www.fnbcorporation.com A replay of the conference call will be available until
June 21, 2001, by dialing 1-800-428-6051 (passcode: 196083).

                                    # # # # #

Copies of this news release are available over the Internet at
www.fnbcorporation.com or by contacting F.N.B.'s Corporate Affairs Department at
1-800-262-7600, extension 1676.

This release contains forward-looking statements within the meaning of the
Private Securities Litigation Reform Act of 1995. Such statements include, but
are not limited to, (i) statements about the potential or expected benefits of a
merger between F.N.B. Corporation and Promistar Financial Corporation, including
future financial and operating results, cost savings and affect on earnings per
share that may be realized from the merger; (ii) statements with respect to
F.N.B.'s plans, objectives and intentions for the merger and for the operation
of the combined company; and (iii) other statements identified by words such as
"believes", "expects", "anticipates", "estimates", "intends", "plans",
"targets", "projects", and similar expressions. These statements are based upon
the current beliefs and expectations of the management of F.N.B. Corporation and
Promistar Financial Corporation and are subject to significant risks and
uncertainties. Actual results may differ from those set forth in the
forward-looking statements.

The following factors, among others, could cause actual results to differ
materially from the anticipated results or other expectations expressed in the
forward-looking statements: (1) the businesses of F.N.B. or Promistar may not be
integrated successfully or such integration may be more difficult,
time-consuming or costly than expected; 2) Promistar


   5

has not yet consummated its acquisition of FNH Corporation and such acquisition
may experience delays or integration problems; (3) expected revenue synergies
and cost savings from the merger may not be fully realized within the expected
time frame or at all; (4) revenues following the merger may be lower than
expected; (5) deposit attrition, operating costs, customer loss and business
disruption, including, without limitation, difficulties in maintaining
relationships with employees, customers, clients or suppliers, may be greater
than expected following the merger; (6) the regulatory approvals required for
the merger may not be obtained on the proposed terms or on the anticipated
schedule; (7) the failure of F.N.B.'s or Promistar's shareholders to approve the
merger; (8) competitive pressures among depository and other financial
institutions may increase significantly and may have an effect on pricing,
spending, third-party relationships and revenues; (9) the strength of the United
States economy in general and the strength of the local economies in which the
combined company will conduct operations may be different than expected,
resulting in, among other things, a deterioration in credit quality or a reduced
demand for credit, including the resultant effect on the combined company's loan
portfolio and allowance for loan losses; and (10) changes in the United States
and foreign legal and regulatory framework.

F.N.B. will file with the SEC a Registration Statement on Form S-4, which will
contain the prospectus of F.N.B. relating to the shares to be issued in the
merger, and the proxy statements of F.N.B. and Promistar relating to the special
meetings of shareholders of F.N.B. and Promistar at which the merger agreement
will be considered and voted upon by their respective shareholders, as well as
other relevant documents concerning the proposed merger. Investors are urged to
read the joint proxy statement/prospectus when it becomes available and any
other relevant documents filed with the SEC because they will contain important
information. You will be able to obtain the Form S-4 Registration Statement,
including the exhibits filed therewith free of charge at the website maintained
by the SEC at www.sec.gov. In addition, you may obtain documents filed with the
SEC by F.N.B. free of charge by requesting them in writing from F.N.B.
Corporation, 2150 Goodlette Road North, Naples, Florida 34102, Attention:
Corporate Secretary, or by telephone at (800) 262-7600. You may obtain documents
filed with the SEC by Promistar free of charge by requesting them in writing
from Promistar, 551 Main Street, Post Office Box 1146, Johnstown, Pennsylvania
15901-1146, Attention: Corporate Secretary, or by telephone at (814) 532-3801.

F.N.B., Promistar and their directors and executive officers may be deemed to be
participants in the solicitation of proxies from their respective shareholders
in connection with the merger. Information about such directors and executive
officers and their ownership of F.N.B. and Promistar stock is set forth in the
proxy statements for each company's 2001 annual meeting of shareholders which
will be incorporated by reference in the Form S-4 Registration Statement to be
filed with the SEC and in the joint proxy


   6

statement/prospectus to be mailed to F.N.B. and Promistar shareholders.
Investors may obtain additional information regarding the interests of such
participants by reading the proxy statement/prospectus when it becomes
available.

Investors should read the proxy statement/prospectus carefully when it becomes
available before making any voting or investment decisions.