Commentary
Stewart Baldwin: 'It has been suggested, on the basis of a statement in Dugdale's Monasticon Anglicanum (6:497), in which Llywelyn refers to a certain Walter Corbet as "frater Willielmi Corbet avunculi mei", that Llywelyn's mother was a Corbet. (See, for example, Meisel's Barons of the Welsh Frontier, which, however, does not even mention the Welsh version of Llywelyn's maternity in JC.) However, as the source of JC.29 appears to have been written during Llywelyn's lifetime, and there are others ways in which an uncle-nephew relationship between William Corbet (an obscure individual) and Llywelyn could be explained, there seems to be no good reason to reject the statement of JC.29 regarding the identity of Llywelyn's mother.'
Family
ClaimDetailEvidence
FatherMadog ap Maredudd, Prince of Powys (e1090-1160) [S756] [S934] [S2730]
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SpouseIorwerth Drwyndwn ap Owain, Prince of North Wales (e1131-1174) 
Child +Llywelyn Fawr ap Iorwerth, Prince of North Wales (~1173-1240) [S756] [S934] [S2730]
research
Attributes
ClaimDetailEvidence
GenderFemale
NameMargred ferch Madog [S2730]
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NameMarared of Powys [S934]
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NameMarared [S756]
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FatherMadog ap Maredudd, Prince of Powys (e1090-1160) [S756] [S934] [S2730]
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Timeline
ClaimDateDetailAgeEvidence
Birthest 1133 (1133-1150)
 
Sources
IndexTitle
[S756] Weis, Frederick Lewis, "Ancestral Roots of Sixty Colonists Who Came To New England before 1700, 7th Ed." (Genealogical Publishing Co., Inc., Baltimore, 1999).
[S934] Cawley, Charles, "Foundation of Medieval Genealogy (Medieval Lands - Wales)" (2006-7 (v1.1 Updated 12 April 2007)) (https://fmg.ac/Projects/MedLands/WALES.htm).
[S2730] Baldwin, Stewart, "Medieval Genealogy Newsgroup: Llywelyn ap Iorwerth Ancestor Table" (http://sites.rootsweb.com/~medieval/llywelyn.htm).
Kinship Lines for Margred ferch Madog
Spouse/PartnerDegreeRelationshipMRCA
Iorwerth Drwyndwn ap Owain, Prince of North Wales (e1131-1174)93rd Cousin 1x removedCynfyn ap Gwerstan, King of Powys (e988-)
Iorwerth Drwyndwn ap Owain, Prince of North Wales (e1131-1174)188th CousinRhodri Mawr ap Merfyn, King of Gwynedd & Seisyllwg (e817-878)