Family: 4th Earl of Hertford Gilbert De Clare / Isabel Marshal (F5118)
The parent family of Lady Isabella De Clare is the Family.
3rd Earl of Hertford Richard De Clare (1153-1218) 
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Countess of Gloucester Amice Fitzrobert (1160-1220)
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Maud De Clare (1184-1213)  |
| Richard De Clare (1184-1228) |
| 1st Earl of Pembroke William Marshal (1146-1219)
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| Lady Abergavenny Eva Marshal (1203-1246) |
| 2nd Earl of Pembroke William Marshal (1190-1231) |
| 3rd Earl of Pembroke Richard Marshal (1191-1234) |
| Mehelt Marshal (1194-1248) |
| 4th Earl of Pembroke Gilbert Marshal (1197-1241) |
| 5th Earl of Pembroke Walter Marshal (1199-1245) |
| Sibyl Marshal (1201-1245) |
| 6th Earl of Pembroke Anselm Marshal (1198-1245) |
| Joan Marshal (1202-1234) |
 | 4th Earl of Hertford Gilbert De Clare (1180-1230)
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| Isabel Marshal (1200-1240)
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| Agnes De Clare (1218- ) |
| Amice De Clare (1220-1287) |
| William De Clare (1228-1258) |
 | Gilbert De Clare (1229- ) |
| Lady Isabella De Clare (1226-1264) |
