Exhibit 99.1

ALLEGHANY CORPORATION
7 Times Square Tower
17th Floor
New York, NY 10036

    Contact:   Robert M. Hart
    (212) 752-1356

                                                           FOR IMMEDIATE RELEASE

ALLEGHANY COMPLETES SALE OF INDUSTRIAL MINERALS BUSINESS

            NEW YORK, N.Y. - JULY 14, 2005 - Alleghany Corporation (NYSE: Y)
announced today that the previously announced sale of its world-wide industrial
minerals business, World Minerals Inc., to Imerys USA, Inc., a wholly-owned
subsidiary of Imerys, S.A., had been completed. Under the terms of the
transaction, Alleghany received a purchase price of approximately $217,000,000.
Alleghany anticipates that the transaction will result in a modest after-tax
gain.

            Alleghany is engaged through its subsidiary Alleghany Insurance
Holdings LLC (consisting of RSUI Group, Inc., Capitol Transamerica Corporation
and Darwin Professional Underwriters, Inc.) in the property and casualty
insurance business.

            This press release contains forward-looking statements with respect
to the anticipated effects of the transaction. Actual results of the transaction
could be significantly different. Factors that could affect results include
those set forth in filings made by Alleghany with the Securities and Exchange
Commission. Although forward-looking statements help to provide complete
information about future prospects, readers should keep in mind that
forward-looking statements are much less reliable than historical information.

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