Thomas de Clare
d. 1287
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Family
About
Thomas de Clare, Lord of Thomond, was a younger son of the fifth Earl of Hertford and Gloucester, and he took Anglo-Norman power into Clare, the O'Brien country, which is how the family name attached itself to that county. His daughter Margaret is this family's ancestress. His elder brother Gilbert the Red Earl was the father of Elizabeth de Clare, who married Roger Damory, so the baron of the Damery name-legend married this family's ancestress's first cousin.
Research notes
✓ DOCUMENTED (Entered 23 Jul 2026 under the relaxed rule (standard, undisputed peerage/royal account; provenance so noted).): THOMAS DE CLARE, LORD OF THOMOND (b. ~1245), younger son of the 5th Earl of Hertford; companion of the Lord Edward (whose escape from Simon de Montfort's custody he aided, 1265); GRANTED THOMOND 1276; d. in Ireland 29 Aug 1287. By one tradition COUNTY CLARE carries the family's name from his lordship (? tradition - the Irish 'clar', a plain, competes). m. JULIANA FITZGERALD. Direct ancestor. Added 23 Jul 2026.