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                                                                    Exhibit 4.12



                              CERTIFICATE OF TRUST

                                       OF

                        TRENWICK AMERICA CAPITAL TRUST I


        THIS Certificate of Trust of Trenwick America Capital Trust I (the
"Trust"), dated as of June 15, 2001, is being duly executed and filed by the
undersigned, as trustees, to form a business trust under the Delaware Business
Trust Act (12 DEL. C. Sections 3801, et seq.).

        1.     Name.  The name of the business trust formed hereby is Trenwick
America Capital Trust I.

        2.     Delaware Trustee.  The name and business address of the trustee
of the Trust with a principal place of business in the State of Delaware is Bank
One Delaware, Inc., Three Christiana Center; 201 N. Walnut Street; Wilmington,
Delaware 19801.

        3.     Effective Date.  This Certificate of Trust shall be effective
upon filing with the Secretary of the State of the State of Delaware.





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        IN WITNESS WHEREOF, the undersigned, being the trustees of the Trust,
have executed this Certificate of Trust as of the date first-above written.

                                BANK ONE TRUST COMPANY, N.A., as trustee
                                   of the Trust

                                By:         /s/ Sandra L. Caruba
                                    ----------------------------------
                                    Name:     Sandra L. Caruba
                                            --------------------------
                                    Title:    Vice President
                                            --------------------------


                                BANK ONE DELAWARE, INC., as trustee of the
                                Trust

                                By:         /s/ Sandra L. Caruba
                                    ----------------------------------
                                    Name:     Sandra L. Caruba
                                            --------------------------
                                    Title:    Vice President
                                            --------------------------

                                JOHN V. DEL COL, as Administrative Trustee


                                            /s/ John V. Del Col
                                --------------------------------------
                                            John V. Del Col



                                YVONNE M. POSTER, as Administrative Trustee


                                            /s/ Yvonne M. Poster
                                --------------------------------------
                                             Yvonne M. Poster



                                DAVID M. FINKELSTEIN, as Administrative
                                  Trustee


                                            /s/ David M. Finkelstein
                                --------------------------------------
                                             David M. Finkelstein