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                                                                     EXHIBIT 5.2

                 [Letterhead of Richards, Layton & Finger, P.A.]


                                September 5, 2002


Marathon Financing Trust I
c/o Marathon Oil Corporation
5555 San Felipe Road
Houston, Texas  77056-2723

          Re:  MARATHON FINANCING TRUST I

Ladies and Gentlemen:

          We have acted as special Delaware counsel for Marathon Oil
Corporation, a Delaware corporation (the "Company"), and Marathon Financing
Trust I, a Delaware statutory trust (the "Trust"), in connection with the
matters set forth herein. At your request, this opinion is being furnished to
you.

          For purposes of giving the opinions hereinafter set forth, our
examination of documents has been limited to the examination of originals or
copies of the following:

          (a)  The Certificate of Trust of the Trust, dated as of August 29,
2002 (the "Certificate"), as filed in the office of the Secretary of State of
the State of Delaware (the "Secretary of State") on August 30, 2002;

          (b)  The Declaration of Trust, dated as of August 29, 2002, among the
Company, as sponsor, and the trustees of the Trust named therein;

          (c)  The Registration Statement (the "Registration Statement") on Form
S-3, including a preliminary prospectus (the "Prospectus") relating to the Trust
Preferred Securities of the Trust representing preferred undivided beneficial
interests in the assets of the Trust (each, a "Trust Preferred Security" and
collectively, the "Trust Preferred Securities"), as proposed to be filed by the
Company, the Trust and others with the Securities and Exchange Commission on or
about September 5, 2002;

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Marathon Financing Trust I
September 5, 2002
Page 2


          (d)  A form of Amended and Restated Declaration of Trust of the Trust,
to be entered into among the Company, as sponsor, the trustees of the Trust
named therein, and the holders, from time to time, of undivided beneficial
interests in the assets of the Trust (including Exhibits A, B and C thereto)
(the "Declaration"), attached as an exhibit to the Registration Statement; and

          (e)  A Certificate of Good Standing for the Trust, dated September 3,
2002, obtained from the Secretary of State.

          Capitalized terms used herein and not otherwise defined are used as
defined in the Declaration.

          For purposes of this opinion, we have not reviewed any documents other
than the documents listed in paragraphs (a) through (e) above. In particular, we
have not reviewed any document (other than the documents listed in paragraphs
(a) through (e) above) that is referred to in or incorporated by reference into
the documents reviewed by us. We have assumed that there exists no provision in
any document that we have not reviewed that is inconsistent with the opinions
stated herein. We have conducted no independent factual investigation of our own
but rather have relied solely upon the foregoing documents, the statements and
information set forth therein and the additional matters recited or assumed
herein, all of which we have assumed to be true, complete and accurate in all
material respects.

          With respect to all documents examined by us, we have assumed (i) the
authenticity of all documents submitted to us as authentic originals, (ii) the
conformity with the originals of all documents submitted to us as copies or
forms, and (iii) the genuineness of all signatures.

          For purposes of this opinion, we have assumed (i) that the Declaration
and the Certificate are in full force and effect and have not been amended, (ii)
except to the extent provided in paragraph 1 below, that each of the parties to
the documents examined by us has been duly created, organized or formed, as the
case may be, and is validly existing in good standing under the laws of the
jurisdiction governing its creation, organization or formation, (iii) the legal
capacity of natural persons who are signatories to the documents examined by us,
(iv) that each of the parties to the documents examined by us has the power and
authority to execute and deliver, and to perform its obligations under, such
documents, (v) that each of the parties to the documents examined by us has duly
authorized, executed and delivered such documents, (vi) that each Person to whom
a Trust Preferred Security is to be issued by the Trust (collectively, the
"Preferred Security Holders") will receive a Preferred Securities Certificate
for such Trust Preferred Security and will pay for the Trust Preferred Security
acquired by it, in accordance with the Declaration and the Registration
Statement, and (vii) that the Trust Preferred Securities will be issued and sold
to the Preferred Security Holders in accordance with the Declaration and the
Registration Statement. We have not participated in the preparation of the
Registration Statement and assume no responsibility for its contents.

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Marathon Financing Trust I
September 5, 2002
Page 3


          This opinion is limited to the laws of the State of Delaware
(excluding the securities laws and blue sky laws of the State of Delaware), and
we have not considered and express no opinion on the laws of any other
jurisdiction, including federal laws and rules and regulations relating thereto.
Our opinions are rendered only with respect to Delaware laws and rules,
regulations and orders thereunder that are currently in effect.

          Based upon the foregoing, and upon our examination of such questions
of law and statutes of the State of Delaware as we have considered necessary or
appropriate, and subject to the assumptions, qualifications, limitations and
exceptions set forth herein, we are of the opinion that:

          1.   The Trust has been duly created and is validly existing in good
standing as a statutory trust under the Delaware Statutory Trust Act (12 DEL. C.
Section 3801, ET SEQ.).

          2.   The Trust Preferred Securities will represent valid and, subject
to the qualifications set forth in paragraph 3 below, fully paid and
nonassessable undivided beneficial interests in the assets of the Trust.

          3.   The Preferred Security Holders, as beneficial owners of the
Trust, will be entitled to the same limitation of personal liability extended to
stockholders of private corporations for profit organized under the General
Corporation Law of the State of Delaware. We note that the Preferred Security
Holders may be obligated pursuant to the Declaration to (a) pay taxes or other
governmental charges that may be imposed in connection with any transfer or
exchange of Trust Preferred Securities or the issuance of replacement Preferred
Securities Certificates and (b) provide reasonable security and indemnity in
connection with requests of or directions to the Property Trustee to exercise
its rights and remedies under the Declaration.

          We consent to the filing of this opinion with the Securities and
Exchange Commission as an exhibit to the Registration Statement. In addition, we
hereby consent to the use of our name under the heading "Legal Matters" in the
Prospectus. In giving the foregoing consents, we do not thereby admit that we
come within the category of Persons whose consent is required under Section 7 of
the Securities Act of 1933, as amended, or the rules and regulations of the
Securities and Exchange Commission thereunder. Except as stated above, without
our prior written consent, this opinion may not be furnished to, or relied upon
by, any other Person for any purpose.

                                       Very truly yours,


                                       /s/ Richards, Layton & Finger, P.A.