UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C. 20549

                               Amendment No. 1 to
                                  SCHEDULE 13D

                   Under the Securities Exchange Act of 1934

                               Markel Corporation
                                (Name of Issuer)

                      Common Stock, no par value per share
                         (Title of Class of Securities)

                                   570535104
                                 (CUSIP Number)

                                Jean M. Waggett
                   Senior Vice President and General Counsel
                       Terra Nova (Bermuda) Holdings Ltd.
                      Richmond House, 12 Par-la-Ville Road
                            Hamilton, HM 08, Bermuda
                                 (441) 292-7731
            (Name, Address and Telephone Number of Person Authorized
                     to Receive Notices and Communications)

                                January 28, 2000

            (Date of Event which Requires Filing of this Statement)

     If the filing person has previously filed a statement on Schedule 13G to
report the acquisition which is the subject of this Schedule 13D, and is filing
this schedule because of Sections 240.13d-1(3), 240.13d-1(f) or 240.13d-1(g),
check the following box [_].

               Note: Schedules filed in paper format shall include a signed
          original and five copies of the schedule, including all exhibits. See
          Section 240.13d-7(b) for other parties to whom copies are to be sent.

     The information required on the remainder of this cover page shall not be
deemed to be "filed" for the purposes of Section 18 of the Securities Exchange
Act of 1934 ("Act") or otherwise subject to the liabilities of that section of
the Act but shall be subject to all other provisions of the Act (however, see
the Notes).


   * The remainder of this cover page shall be filled out for a reporting
person's initial filing on this form with respect to the subject class of
securities, and for any subsequent amendment containing information which would
alter disclosures provided in a prior cover page.

(1)  Names of Reporting Persons
     --------------------------

     Terra Nova (Bermuda) Holdings Ltd.

     S.S. or I.R.S. Identification Nos. of Above Persons
     ---------------------------------------------------

     N/A

(2)  Check the Appropriate Box if a Member of a Group
     ------------------------------------------------

     (a) [_]
     (b) [X]

(3)  SEC Use Only
     ------------

(4)  Source of Funds
     ---------------

     OO

(5)  Check if Disclosure of Legal Proceedings is Required Pursuant to Items 2(d)
     ---------------------------------------------------------------------------
     or 2(e)
     -------

     [_]

(6)  Citizenship or Place of Organization
     ------------------------------------

     Bermuda

Number of Shares                   (7)  Sole Voting Power                      0
Beneficially Owned
by Each Reporting
Person With
                                   (8)  Shared Voting Power              914,426
                                   (9)  Sole Dispositive Power                 0
                                   (10) Shared Dispositive Power               0

(11) Aggregate Amount Beneficially Owned by Each Reporting Person
     ------------------------------------------------------------

     914,426

                                       2


(12) Check if the Aggregate Amount in Row (11) Excludes Certain Shares
     -----------------------------------------------------------------

     [_]

(13) Percent of Class Represented by Amount in Row 11
     ------------------------------------------------

     16.3%

(14) Type of Reporting Person
     ------------------------

     HC, IC

Items 4 and 7 are amended as set forth below:

Item 4. Purpose of Transaction.
        ----------------------

   The Merger Agreement provides, subject to the terms and conditions set forth
therein, for (i) the merger ("Merger") of MINT Sub Ltd., a corporation to be
organized under the laws of Virginia as a wholly-owned subsidiary of Virginia
Holdings Inc. ("MINT"), a corporation to be organized under the laws of
Virginia, with and into Markel and (ii) a Scheme of Arrangement between Terra
Nova and certain of its shareholders (the "Scheme"). Upon completion of the
Merger and the Scheme, each of Markel and Terra Nova will be a wholly-owned
subsidiary of MINT, which will be renamed Markel Corporation.

   The consummation of the transactions contemplated by the Merger Agreement is
subject to regulatory approvals and the satisfaction or waiver of a number of
other conditions as more fully described in the Merger Agreement.

   In connection with the Merger, and as an inducement to Terra Nova to enter
into the Merger Agreement, the shareholders of Markel set forth in Item 5 (each
a "Stockholder" and, collectively, the "Stockholders"), who collectively own
914,426 shares of the Common Stock of Markel, representing 16.3% of the Common
Stock currently outstanding, have entered into a Stockholders Agreement, dated
as of August 15, 1999, with Markel and Terra Nova (the "Stockholders
Agreement").

   Pursuant to the terms of the Stockholders Agreement, as long as the
Stockholders Agreement is in force, each Stockholder irrevocably appoints Terra
Nova or any designee the lawful agent, attorney and proxy of such Stockholder to
vote the shares of Markel's Common Stock held of record or beneficially by such
Stockholder (collectively, the "Shares") (i) in favor of the Scheme, the
execution and delivery by Markel of the Merger Agreement and the approval of the
terms thereof and each of the other actions contemplated by the Merger
Agreement, the Stockholders Agreement and any actions required in furtherance
thereof; (ii) against any action or agreement that would result in a

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breach of any covenant, representation or warranty or any other obligation or
agreement of Markel under the Merger Agreement or the Stockholders Agreement;
and (iii) against the following actions (other than the Scheme and the
transactions contemplated by the Merger Agreement): (1) any extraordinary
corporate transaction, such as a merger, consolidation, amalgamation or other
business combination involving Markel or its subsidiaries; (2) a sale, lease or
transfer, of a material amount of assets of Markel or its subsidiaries or a
reorganization, recapitalization, dissolution or liquidation of Markel or its
subsidiaries; (3)(a) any change in the majority of the Board of Directors of
Markel; (b) any material change in the present capitalization of Markel or any
material amendment of Markel's certificate of incorporation and memorandum of
association; (c) any other material change in Markel's corporate structure or
business; or (d) any other action which, is intended, or could reasonably be
expected, to impede, interfere with, delay, postpone, discourage or materially
adversely affect the Scheme or the transactions contemplated by the Merger
Agreement or the Stockholders Agreement or the contemplated economic benefits of
any of the foregoing.

   The Stockholders have also agreed, while the Stockholders Agreement is in
force, not to sell, transfer, pledge, encumber, assign or otherwise dispose of,
or enter into any contract option or other arrangement or understanding with
respect to the sale, transfer, pledge, encumbrance, assignment or other
disposition of, any of the Shares, or grant any proxies, deposit any Shares into
a voting trust or enter into a voting agreement with respect to any Shares or
take any action that would make any representation or warranty of such
Stockholder contained in the Stockholders Agreement untrue or incorrect or have
the effect of preventing or disabling such Stockholder from performing his or
its obligations under the Stockholders Agreement.

   The Stockholders Agreement terminates at the earlier of the effective time of
the Merger and the Scheme or the termination of the Merger Agreement in
accordance with its terms.

   The Merger Agreement provides that the parties thereto shall procure at the
effective time of the Scheme, that only those directors of Terra Nova and such
additional persons, in each case who shall be designated by MINT shall remain or
be elected to serve as directors of Terra Nova, each of such directors to hold
office in accordance with the applicable provisions of the articles of
association of Terra Nova and until their successors shall be elected or
appointed and shall duly qualify.

   Following the Merger, Markel will become a wholly-owned subsidiary of MINT.
The shares of Common Stock will be delisted from the New York Stock Exchange and
will be eligible for termination of registration under Section 12(g)(4) of the
Securities Exchange Act of 1934, as amended.

                                       4


   On January 31, 2000, Markel and Terra Nova jointly announced that they had
entered into a definitive agreement to revise the terms of their August 15, 1999
Merger Agreement ("Amendment No. 2") and that the revised transaction had been
approved by their respective Boards of Directors.

   The Merger Agreement, Amendment No. 2 and the Stockholders Agreement are
incorporated herein by reference. The descriptions of the Merger and the Scheme,
and the terms of the Merger Agreement and the Stockholders Agreement, contained
herein are summaries, and qualified in their entirety by reference to the
Exhibits 1 through 3 hereto which are incorporated herein by reference.

Item 7. Materials to Be Filed as Exhibits.
        ---------------------------------

Exhibit No.
- -----------

   1           The Stockholders Agreement by and among Markel Corporation, Terra
               Nova (Bermuda) Holdings Ltd. and the shareholders of Markel
               Corporation named therein dated as of August 15, 1999
               (incorporated herein by reference to Exhibit 99.3 to Markel's
               Form 8-K filed August 20, 1999, File No. 001-13051 (the "Form 8-
               K")).
   2           The Agreement and Plan of Merger and Scheme of Arrangement
               between Markel Corporation and Terra Nova (Bermuda) Holdings Ltd.
               dated as of August 15, 1999 (incorporated herein by reference to
               Exhibit 99.1 to the Form 8-K).
   3           Amendment No. 2 to the Agreement and Plan of Merger and Scheme of
               Arrangement dated as of January 28, 2000 filed as Exhibit 99.2 to
               Terra Nova's Form 8-K filed February 4, 2000, is incorporated
               herein by reference.

                                       5


                                   Signature

   After reasonable inquiry and to the best of my knowledge and belief, I
certify that the information set forth in this statement is true, complete and
correct.

Dated: February 8, 2000

                                   TERRA NOVA (BERMUDA) HOLDINGS LTD.



                                   By: /s/ Jean M. Waggett
                                       ---------------------------------------
                                       Name:  Jean M. Waggett
                                       Title: Senior Vice President and
                                              General Counsel

                                       6


                               INDEX OF EXHIBITS

Exhibit No.
- -----------
     1         The Stockholders Agreement by and among Markel Corporation, Terra
               Nova (Bermuda) Holdings Ltd. and the shareholders of Markel
               Corporation named therein dated as of August 15, 1999
               (incorporated herein by reference to Exhibit 99.3 to Markel's
               Form 8-K filed August 20, 1999, File No. 001-13051 (the "Form 8-
               K")).
     2         The Agreement and Plan of Merger and Scheme of Arrangement
               between Markel Corporation and Terra Nova (Bermuda) Holdings Ltd.
               dated as of August 15, 1999 (incorporated herein by reference to
               Exhibit 99.1 to the Form 8-K).
     3         Amendment No. 2 to the Agreement and Plan of Merger and Scheme of
               Arrangement dated as of January 28, 2000 filed as Exhibit 99.2 to
               Terra Nova's Form 8-K filed February 4, 2000, is incorporated
               herein by reference.

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