Exhibit 5.1




                                                           Effective Date:
                                                           14 May, 2001


ACE Limited
The ACE Building
30 Woodbourne Avenue
Hamilton HM 08
Bermuda.


Dear Sirs,

Re:      ACE Limited (the "Company") - Form S-8 Registration Statement
         1998 Long-Term Incentive Plan ("the Plan")
         ------------------------------------------

You have asked us to render this opinion in our capacity as your counsel as
to Cayman Islands law in connection with the registration pursuant to a
Registration Statement on Form S-8 (the "Registration Statement") under the
Securities Act of 1933, as Amended (the "Act") of 11,569,184 of the
Company's Ordinary Shares, par value US$0.041666667 per share (the
"Ordinary Shares") to be issued pursuant to the Plan approved by Board
Resolution on 13 November, 1998 and 23 February, 2001 and by resolutions of
shareholders at the Annual General Meetings of the Company held on 5
February, 1999 and 11 May, 2001.

We have reviewed the Company's Memorandum and Articles of Association (as
amended). We have relied in giving this opinion on certifications from the
Company's Officers.

We assume that all subscription monies due in respect of shares issued by
the Company have been or will be duly received by the Company. We further
assume that all Ordinary Shares to be newly issued in accordance with the
Plan have been reserved for issuance and that there are no intervening
changes in the Plan, the Company's Memorandum and Articles of Association,
the laws of the Cayman Islands or any other relevant matter.

On the basis of the foregoing, we would advise as follows:-

1.       The Company's authorised capital includes 300,000,000 Ordinary
         Shares of US$0.041666667 each and 10,000,000 "Other Shares" of
         US$1.00 each.

2.       The Company has sufficient authorised share capital to issue the
         11,569,184 Ordinary Shares and the issue thereof is within the power
         of the Company's Board of Directors. The Ordinary Shares to be issued
         in accordance with the Plan have been duly authorised and when issued
         and registered in the Company's Share Register in accordance with
         the provisions of the Plan will be legally and validly issued.

3.       On the basis that the contractual subscription price (being not
         less than the par value) of the Ordinary Shares is fully paid in
         cash or other consideration approved by the Board of Directors or
         a duly established Committee thereof, such Ordinary Shares issued
         or to be issued may properly be credited as fully paid under
         Cayman Islands law.




4.       Fully paid shares are not subject to further calls or assessments by
         the Company.

5.       The Company has been incorporated as an exempted company under the
         Companies Law of the Cayman Islands and the liability of its
         shareholders is limited to the amount, if any, unpaid on their
         shares (see Clause 5 of the Memorandum of Association). On the
         basis that all such shares are fully paid, there is no rule of
         Cayman Islands law that would impose any further liability on
         person holding shares in the Company, merely by reason of such
         shareholding.

We hereby consent to the filing of this opinion as an exhibit to the
Registration Statement.



                                                  Yours faithfully,




                                                  Maples and Calder