Ownership Submission
FORM 3
 UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940
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(Print or Type Responses)
1. Name and Address of Reporting Person *
  BYRNE MARK JAMES
 2. Date of Event Requiring Statement (Month/Day/Year)
03/29/2007		 3. Issuer Name and Ticker or Trading Symbol
Flagstone Reinsurance Holdings Ltd [FSR]
(Last)
(First)
(Middle)
FLAGSTONE REINSURANCE HOLDINGS LIMITED, 23 CHURCH STREET		 4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
__X__ Director __X__ 10% Owner
__X__ Officer (give title below) _____ Other (specify below)
Executive Chairman
 5. If Amendment, Date Original Filed(Month/Day/Year)
(Street)

HAMILTON, D0, HM11 		 6. Individual or Joint/Group Filing(Check Applicable Line)
_X_ Form filed by One Reporting Person
___ Form filed by More than One Reporting Person
(City)
(State)
(Zip)
Table I - Non-Derivative Securities Beneficially Owned
1.Title of Security
(Instr. 4)		 2. Amount of Securities Beneficially Owned
(Instr. 4)		 3. Ownership Form: Direct (D) or Indirect (I)
(Instr. 5)		 4. Nature of Indirect Beneficial Ownership
(Instr. 5)
Common Shares 9,740,000
I
See Footnote (1)

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly. SEC 1473 (7-02)
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Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 4)		 2. Date Exercisable and Expiration Date
(Month/Day/Year)		 3. Title and Amount of Securities Underlying Derivative Security
(Instr. 4)		 4. Conversion or Exercise Price of Derivative Security 5. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 5)		 6. Nature of Indirect Beneficial Ownership
(Instr. 5)
Date Exercisable Expiration Date Title Amount or Number of Shares
Warrant 12/01/2010 12/31/2010 Common Shares 8,362,518 $ 14 I See Footnote (2)

Reporting Owners

Reporting Owner Name / Address Relationships
Director 10% Owner Officer Other
BYRNE MARK JAMES
FLAGSTONE REINSURANCE HOLDINGS LIMITED
23 CHURCH STREET
HAMILTON, D0, HM11 		   X   X   Executive Chairman  

Signatures

/s/ Mark J. Byrne 03/29/2007
**Signature of Reporting Person Date

Explanation of Responses:

* If the form is filed by more than one reporting person, see Instruction 5(b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1) These shares represent the indirect proportionate interest of the reporting person in 10,000,000 common shares of the issuer held of record by Haverford (Bermuda) Limited, based upon the proportionate contribution of the reporting person to the capital of Haverford (Bermuda) Limited. The reporting person may be deemed to have investment or voting control over Haverford (Bermuda) Limited. These shares are held through a trust for the benefit of others and the reporting person therefore disclaims beneficial ownership of these shares.
(2) These shares represent the indirect proportionate interest of the reporting person in a warrant, to be exercisable for 8,585,747 common shares, held of record by Haverford (Bermuda) Limited, based upon the proportionate contribution of the reporting person to the capital of Haverford (Bermuda) Limited. The reporting person may be deemed to have investment or voting control over Haverford (Bermuda) Limited. The warrant is held through a trust for the benefit of others and the reporting person therefore disclaims beneficial ownership of the warrant.

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