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                                                                     Exhibit 5.1

                                MAPLES AND CALDER
                               Cayman Europe Asia

ACE Limited
The ACE Building
30 Woodbourne Building
Hamilton, HM 08
Bermuda


31 August, 2004


Dear Sirs

ACE LIMITED

We have acted as Cayman Islands legal advisers to ACE Limited (the "COMPANY")
in connection with the Company's registration statement on Form S-3,
including all amendments or supplements thereto (the "REGISTRATION
STATEMENT"), filed with the Securities and Exchange Commission under the
Securities Act of 1933, as amended, relating, to the offering and sale, INTER
ALIA, of ordinary shares of the Company (the "ORDINARY SHARES"), preferred
shares of the Company (the "PREFERRED SHARES"), depositary shares
representing preferred shares of the Company (the "DEPOSITARY SHARES"), debt
securities (the "DEBT SECURITIES"), warrants to purchase ordinary shares (the
"WARRANTS TO PURCHASE ORDINARY SHARES"), warrants to purchase preferred
shares (the "WARRANTS TO PURCHASE PREFERRED SHARES"), warrants to purchase
debt securities (the "WARRANTS TO PURCHASE DEBT SECURITIES" and, together
with the Warrants to Purchase Ordinary Shares and the Warrants to Purchase
Preferred Shares, the "WARRANTS"), stock purchase contracts (the "STOCK
PURCHASE CONTRACTS") and stock purchase units (the "STOCK PURCHASE UNITS") of
the Company and debt securities of ACE INA Holdings Inc. ("ACE INA")
guaranteed by the Company (the "ACE INA DEBT SECURITIES"), in one or more
offerings up to an aggregate initial offering price of US$1,500,000,000.  We
are furnishing this opinion as Exhibit 5.1 to the Registration Statement.

1    DOCUMENTS REVIEWED

For the purposes of this opinion, we have reviewed only originals, copies or
final drafts of the following documents:

1.1  the certificate of incorporation of the Company and the Memorandum and
Articles of Association of the Company as adopted on 14 January, 1993 and
amended on February, 1998 and 22 January, 2002;

1.2  a Certificate of the Assistant Secretary of the Company (the
"SECRETARY'S CERTIFICATE") in the form attached certifying, INTER ALIA, that
certain resolutions were passed by the

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MAPLES CALDER
Cayman Europe Asia
                                             2

Board of Directors of the Company on 27 May, 2004 ( the "RESOLUTIONS");

1.3  the Registration Statement, including the form of the indenture pursuant
to which the Company's subordinated debt securities will be issued (the "ACE
SUBORDINATED DEBT INDENTURE");

1.4  the Indenture dated as of 15 March, 2002 between the Company and J.P.
Morgan Trust Company, National Association (as successor to The First
National Bank of Chicago) as trustee (the "ACE SENIOR DEBT INDENTURE");

1.5  the Indenture dated as of 1 August, 1999 between the Company, ACE INA
and J.P. Morgan Trust Company, National Association (as successor to The
First National Bank of Chicago) as trustee (the "ACE INA SENIOR DEBT
INDENTURE");

1.6  the Indenture dated as of 1 December, 1999 between the Company, ACE INA
and J.P. Morgan Trust Company, National Association (as successor to The
First National Bank of Chicago) as trustee (the "ACE INA SUBORDINATED DEBT
INDENTURE");

1.7  a Certificate of Good Standing issued by the Registrar of Companies (the
"CERTIFICATE OF GOOD STANDING"); and

1.5  a Certificate of General Counsel and Secretary of the Company in the
form attached.

2    ASSUMPTIONS

The following opinion is given only as to, and based on, circumstances and
matters of fact existing and known to us on the date of this opinion. This
opinion only relates to the laws of the Cayman Islands which are in force on
the date of this opinion. In giving this opinion we have relied (without
further verification) upon the completeness and accuracy of the Officer's
Certificate and the Certificate of Good Standing. We have also relied upon
the following assumptions, which we have not independently verified:

2.1  copy documents, conformed copies or drafts of documents provided to us
are true and complete copies of, or in the final forms of, the originals;

2.2  all signatures, initials and seals are genuine;

2.3  the Company will receive money or money's worth in consideration for the
issue of the Ordinary Shares and the Preferred Shares, and that none of the
Ordinary Shares or the Preferred Shares will be issued for less than par
value;

2.4  there will be sufficient Ordinary Shares and Preferred Shares authorised
for issue under the Company's memorandum of association; and

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MAPLES CALDER
Cayman Europe Asia
                                             3

2.5  there is nothing under any law (other than the law of the Cayman
Islands) which would or might affect the opinions hereinafter appearing.

3    OPINION

Based upon, and subject to, the foregoing assumptions and having regard to
such legal considerations as we deem relevant, we are of the opinion that:

 1.  The Company is an exempted company duly incorporated and validly
existing and, based on the certificate issued by the Cayman Islands Registrar
of Companies, in good standing under the laws of the Cayman Islands.

 2.  With respect to Ordinary Shares (including the Ordinary Shares issuable
upon the exercise of the Ordinary Share Warrants), when the issue of such
Ordinary Shares has been recorded in the share register of the Company and
the subscription price of such Ordinary Shares (being not less than the par
value of the Ordinary Shares) has been fully paid in cash or other
consideration approved by the Board of Directors of the Company or a duly
constituted and acting committee thereof (such Board of Directors or
committee being hereinafter referred to as the Board), the Ordinary Shares
will be authorized and validly issued, fully paid and non-assessable.

 3.  With respect to Preferred Shares (including the Preferred Shares
issuable upon the exercise of the Preferred Share Warrants, and the Preferred
Shares to be represented by the Depositary Shares), when the Board has taken
all necessary corporate action to approve and establish the terms of the
Preferred Shares and related matters, the issue of such Preferred Shares has
been recorded in the share register of the Company and the contractual
subscription price of such Preferred Shares (being not less than the par
value of the Preferred Shares) has been fully paid in cash or other
consideration approved by the Board, the Preferred Shares will be authorized,
validly issued, fully paid and non-assessable.

 4.  With respect to the Warrants and the warrant agreements pursuant to
which the Warrants are to be issued (the "Warrant Agreements"), when the
Board has taken all necessary corporate action to approve the terms of the
Warrants and the Warrant Agreements and related matters, the issue of the
Warrants and the entry by the Company into the Warrant Agreements will be
authorized by the Company.

 5.  The entry by the Company into the ACE Senior Debt Indenture, the ACE INA
Senior Debt Indenture and the ACE INA Subordinated Debt Indenture have been
authorized by the Company. When executed by an Authorized Officer (as defined
in the Resolutions) of the Company, the entry by the Company into the ACE
Subordinated Debt Indenture will be authorized by the Company.

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MAPLES CALDER
Cayman Europe Asia
                                             4

 6.  The Senior Notes to be issued pursuant to the ACE Senior Debt Indenture
have been authorized by the Company. When executed by an Authorized Officer
(as defined in the Resolutions) of the Company, the Subordinated Notes will
be authorized by the Company.

 7.  The guarantee by the Company of the ACE INA Debt Securities has been
authorized.

 8.  The issue by the Company of mandatorily convertible securities has been
authorised, and when the Board has taken all necessary corporate action to
approve the terms of the Stock Purchase Contracts and the issue by the
Company of the Stock Purchase Units, the entry by the Company into the Stock
Purchase Contracts and the issue by the Company of the Stock Purchase Units
will be authorized by the Company.

Except as specifically stated herein, we make no comment with respect to any
representations and warranties which may be made by or with respect to the
Company in any of the documents or instruments cited in this opinion or
otherwise with respect to the commercial terms of the transactions the
subject of this opinion.

We hereby consent to filing of this opinion as an exhibit to the Registration
Statement and to the reference to our firm under the heading "Legal Matters"
in the prospectus included in the Registration Statement.  In the giving our
consent, we do not thereby admit that we are in the category of persons whose
consent is required under Section 7 of the Act or the Rules and Regulations
of the Commission thereunder.

Yours faithfully,


MAPLES AND CALDER
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