1. Lady Isabella Marshal of Pembroke married Gilbert de Clare, 5th Earl of Hertford.
Gilbert de Clare, 5th Earl of Hertford, son of Richard de Clare, 4th Earl of Hertford (1162-1218) and Amice FITZROBERT (c. 1160-1220), was born in 1180. He died on 25 October 1230. He and Lady Isabella Marshal of Pembroke had the following children:
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2. Isabella de Clare, daughter of Gilbert de Clare, 5th Earl of Hertford and Lady Isabella Marshal of Pembroke, was born on 8 November 1226 in Gloucestershire. She married Robert de Brus, 5th Lord Annandale on 12 May 1240. She died on 10 July 1264.
Robert de Brus, 5th Lord Annandale and Isabella de Clare had the following children:
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3. Lord Robert de Brus, son of Robert de Brus, 5th Lord Annandale and Isabella de Clare, was born in 1210. He had the title 'Lord of Annandale'. He died on [Julian] 31 March 1295. He married Christina de Ireby.
Christina de Ireby and Robert de Brus had the following children:
| 5 | Robert le Brus (1243-bef1304). Robert was born in [Julian] 1243. He had the title 'Earl of Carrick'. He had the title 'Earl of Carrick, 6th Lord Annandale'. He died before [Julian] 4 April 1304. |
4. Isabel de Brus was the daughter of Robert de Brus, 5th Lord Annandale and Isabella de Clare.