SECURITIES AND EXCHANGE COMMISSION

                             WASHINGTON, D.C. 20549


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In the Matter of                                          INITIAL CERTIFICATE
Ameren Corporation, et al.                                PURSUANT TO
                                                          RULE 24
File No. 70-10078

(Public Utility Holding Company Act of 1935)
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     This  Certificate  of  Notification  pursuant  to Rule 24 under the  Public
Utility Holding Company Act of 1935, as amended (the "Act"),  is filed by Ameren
Corporation  ("Ameren"),  a  registered  holding  company,  in  connection  with
Ameren's  acquisition  of all of the  issued  and  outstanding  common  stock of
CILCORP Inc.  ("CILCORP"),  an exempt holding company,  from The AES Corporation
("AES"),  as authorized by Order of the Securities and Exchange  Commission (the
"Commission")  dated  January 29,  2003,  in this  proceeding  (Holding  Co. Act
Release No. 27645).  Ameren hereby certifies to the Commission  pursuant to Rule
24 that, on January 31, 2003,  Ameren acquired all of the issued and outstanding
common stock of CILCORP from AES for a total  purchase  price of $1.34  billion,
including debt and preferred stock of CILCORP and its  subsidiaries  that remain
outstanding.

     A "past tense" opinion of counsel is filed as Exhibit F-1(PT) hereto.

                                    SIGNATURE

     Pursuant to the  requirements of the Act, the undersigned  company has duly
caused  this  document to be signed on its behalf by the  undersigned  thereunto
duly authorized.

                                             Ameren Corporation


                                       By: /s/ Steven R. Sullivan
                                          -----------------------------
                                       Name:   Steven R. Sullivan
                                      Title:   Vice President Regulatory Policy,
                                               General Counsel, and Secretary



Dated:  February 5, 2003






                                                                 EXHIBIT F-1(PT)



                        [Steven R. Sullivan letterhead]


                               AMEREN CORPORATION
                              1901 Chouteau Avenue
                            St. Louis, Missouri 63166
                                  314-554-2098

                                February 5, 2003



Securities and Exchange Commission
450 Fifth Street, N.W.
Washington, D.C. 20549

             Re:      Ameren Corporation, et al.
                      Form U-1 Application-Declaration
                      (File No. 70-10078)

Dear Sirs:

     I  refer  to the  Form  U-1  Application/Declaration,  as  amended,  in the
above-referenced  proceeding  (the  "Application"),  under  the  Public  Utility
Holding  Company Act of 1935, as amended (the "Act"),  filed with the Securities
and Exchange Commission (the "Commission") by Ameren Corporation  ("Ameren"),  a
Missouri corporation,  its indirect wholly-owned non-utility subsidiary,  Ameren
Energy Fuels and Services Company  ("Ameren  Fuels"),  an Illinois  corporation,
CILCORP Inc.  ("CILCORP"),  an Illinois  corporation,  and CILCORP's  direct and
indirect public-utility  subsidiaries,  Central Illinois Light Company ("CILCO")
and Central  Illinois  Generation,  Inc.  ("CIGI"),  both of which are  Illinois
corporations  (the  "Applicants");  and to the  order  of the  Commission  dated
January 29, 2003 (Holding Co. Act Release No. 27645) (the "Order") approving the
Application, subject to certain reservations of jurisdiction.  Capitalized terms
used in this letter without  definition have the meanings ascribed to such terms
in the Application.

     Under the Order,  Ameren was  authorized  to acquire  all of the issued and
outstanding  common stock of CILCORP (the  "Transaction").  The  Transaction was
completed  on  January  31,  2003,  as a result of which all of the  issued  and
outstanding  common stock of CILCORP is now held by Ameren.  The Order also made
findings by the  Commission  that  permit  Ameren to retain  CILCORP's  existing
direct and  indirect  non-utility  subsidiaries  and  investments,  with certain
exceptions;  to retain the combined gas utility system of CILCO,  Union Electric
Company and Central Illinois Public Service Company as an additional  integrated
public-utility system; and to retain CILCORP as a subsidiary holding company. In
addition, CILCORP and CILCO were granted an order pursuant to Section 3(a)(1) of
the Act  exempting  each  company,  as a  holding





company,  and its  subsidiary  companies as such from all provisions of the Act,
except  Section  9(a)(2),  and CILCO was  authorized to transfer its  generating
assets to CIGI.

     In addition to the foregoing,  the Commission also authorized the following
related transactions:

     (i)    CILCO to continue to provide certain administrative,  management and
            technical services at  cost  to  CILCORP  and  its  other  associate
            companies for a period not to exceed two years following  closing of
            the Transaction;

     (ii)   Ameren Fuels to enter into separate fuel  services  agreements  with
            CILCO and CIGI pursuant to which Ameren Fuels will manage,  at cost,
            gas supply resources and fuel procurement for CILCO and CIGI;

     (iii)  the issuance of short-term debt securities (i.e., maturities of less
            than  one year) by CILCORP, CILCO and  CIGI in  aggregate amounts at
            any time outstanding during the  Authorization  Period not to exceed
            $250  million  for  each  company,  less  the  amount,  if  any,  of
            short-term borrowings by any of such companies from Ameren;

     (iv)   the issuance of long-term notes by CILCORP to refinance  the CILCORP
            Senior Notes in an  aggregate  principal  amount  not to exceed  the
            current  principal amount of the CILCORP Senior Notes ($475 million)
            plus the amount of any  prepayment or "make whole" premium  required
            to be  paid in connection  with any prepayment of the CILCORP Senior
            Notes, and  the  guarantee of  such notes (or of the CILCORP  Senior
            Notes) by Ameren;

     (v)    the issuance of  Long-term Securities by CIGI in an aggregate amount
            at  any time  outstanding  during  the  Authorization  Period not to
            exceed $500 million;

     (vi)   to the extent not exempt under  Rule 52(a), CILCORP,  CILCO and CIGI
            to  enter  into  and  perform  Interest Rate Hedges and Anticipatory
            Hedges;

     (vii)  CILCORP to issue and  Ameren to acquire  long-term  equity  and debt
            securities in an aggregate amount at any time outstanding during the
            Authorization Period not to exceed $1 billion  and  short-term  debt
            securities (i.e.,  maturities  of up to  one  year)  in an aggregate
            principal amount at any time outstanding  during  the  Authorization
            Period not to exceed $250 million;

     (viii) CIGI to issue and Ameren to acquire  long-term notes in an aggregate
            principal amount at any time  outstanding during  the  Authorization
            Period  not to exceed  $500  million  and  short-term  notes  in  an
            aggregate  principal  amount at  any  time  outstanding  during  the
            Authorization Period not to exceed $250 million;


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     (ix)   CILCO  to  issue  and  Ameren  to  acquire  short-term  notes  in an
            aggregate  principal  amount  at  any time  outstanding  during  the
            Authorization Period not to exceed $250 million;

     (x)    CILCORP to maintain, renew and extend any guarantees and other forms
            of  credit support  that  are  outstanding  on  the  date  that  the
            Transaction  closes, and from time to time during the  Authorization
            Period, to issue new guarantees  and provide  other forms of support
            with respect to securities or other  obligations of its subsidiaries
            in   an   aggregate  amount  at  any  time  outstanding  during  the
            Authorization Period not to exceed $500 million;

     (xi)   CILCORP, CILCO and CIGI to organize and acquire the common  stock or
            other equity securities of one or more Financing Subsidiaries formed
            exclusively  for  the purpose of facilitating  the issuance of long-
            term  debt  or equity  securities of such  companies,  and to issue,
            and any Financing  Subsidiary to  acquire,  Notes  to  evidence  the
            loan of financing  proceeds by any Financing  Subsidiary to CILCORP,
            CILCO or CIGI, as the case may be; and

     (xii)  CILCORP to pay  dividends out of capital or  unearned  surplus in an
            amount  equal to CILCORP's   retained   earnings  at  the  time  the
            Transaction  closes   plus  the   amount,  if  any, recorded  as an
            impairment to  goodwill on the books of CILCORP in  accordance  with
            applicable accounting rules.

     I  have  acted  as  counsel  for  Ameren  and  Ameren  Fuels  (the  "Ameren
Companies")  in  connection  with the  Application  and, as such  counsel,  I am
familiar  with the  corporate  proceedings  taken  by the  Ameren  Companies  in
connection with the Transaction  and related  transactions,  as described in the
Application.  I have examined originals, or copies certified to my satisfaction,
of such  corporate  records  of the  Ameren  Companies,  certificates  of public
officials, certificates of officers and representatives of the Ameren Companies,
and other  documents as I have deemed it necessary to examine as a basis for the
opinions  hereinafter  expressed.  In  such  examination,  I  have  assumed  the
genuineness of all signatures and the authenticity of all documents submitted to
me as originals and the conformity with the originals of all documents submitted
to me as copies.  As to various  questions of fact material to such opinions,  I
have,  when  relevant  facts were not  independently  established,  relied  upon
certificates of officers of the Ameren Companies and other  appropriate  persons
and  statements  contained  in the  Application  and the exhibits  thereto.  The
opinions  expressed below are subject to the following  further  assumptions and
conditions:

     a.   The  authorization  and approval of the  Transaction  by the Boards of
     Directors of Ameren and The AES Corporation, the parent company of CILCORP,
     and, to the extent required,  the  authorization  and approval of the other
     related transactions by the Boards of Directors and shareholders of each of
     the Applicants shall have been adopted and remain in full force and effect;



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     b.   All required approvals,  authorizations,  consents,  certificates, and
     orders of, and all filings and registrations  with, all applicable  federal
     and state  commissions  and  regulatory  authorities  with  respect  to the
     Transaction  and other  related  transactions  shall have been  obtained or
     made,  as the case may be,  and  shall  remain  in  effect  (including  the
     approval and  authorization  of the  Commission  under the Act, the Federal
     Energy Regulatory  Commission under the Federal Power Act, as amended,  and
     the rules and regulations thereunder,  and the Illinois Commerce Commission
     under the applicable  laws of the State of Illinois),  and the  Transaction
     and other related  transactions  shall have been accomplished in accordance
     with all such approvals,  authorizations,  consents, certificates,  orders,
     filings and registrations;

     c.   The applicable  waiting period under the  Hart-Scott-Rodino  Antitrust
     Improvements  Act of  1976,  as  amended,  and the  rules  and  regulations
     thereunder shall have expired;

     d.   The Applicants shall have obtained all consents, waivers and releases,
     if any, required for the Transaction and other related  transactions  under
     all applicable governing corporate documents,  contracts,  agreements, debt
     instruments, indentures, franchises, licenses and permits;

     e.   No act or event other than as  described  herein  shall have  occurred
     subsequent  to the date hereof which would  change the  opinions  expressed
     herein;

     f.   The  Transaction  and  other  related  transactions  shall  have  been
     consummated as described in the Application and under the supervision of me
     and  Jones,  Day,  Reavis  &  Pogue,  Chicago,   Illinois  acting  for  the
     Applicants, and all legal matters incident thereto shall be satisfactory to
     each of us; and

     g.   For purposes of this opinion,  with respect to all matters governed by
     the laws of Illinois and Delaware as applicable to Ameren and Ameren Fuels,
     I have relied upon the opinion of Jones Day,  Chicago,  Illinois,  filed as
     Exhibit F-2 to the Application;  and as to all matters governed by the laws
     of Illinois and Delaware as applicable  to CILCORP,  CILCO and CIGI, I have
     relied upon the opinion of Craig W.  Stensland,  filed as  Exhibit-3 to the
     Application.

     Based upon the foregoing, and subject to the assumptions and conditions set
forth herein, and having regard to legal considerations which I deem relevant, I
am of the opinion that:

     1.   All state laws applicable to the Transaction have been complied with.

     2.   Each of the  Applicants is validly  organized and duly existing  under
     the laws of the state of its incorporation.

     3.   The common  stock of CILCORP  acquired in the  Transaction  is validly
     issued, fully paid and nonassessable, and Ameren, as the holder thereof, is
     entitled


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     to the rights and privileges appertaining thereto set forth in the Articles
     of Incorporation of CILCORP.

     4.   Ameren legally acquired the common stock of CILCORP.

     5.   The  consummation  of the Transaction did not violate the legal rights
     of the holders of any securities  issued by Ameren or any associate company
     of Ameren.

     I hereby consent to the use of this "past tense" opinion in connection with
the  Certificate of Notification  under Rule 24 to which it is an exhibit.  This
"past tense"  opinion is intended  solely for the use of the  Commission and may
not be relied upon by any other person.


                                              Very truly yours,



                                          /s/ Steven R. Sullivan








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