Isabel de Clare, 4th Countess of Pembroke, was born 1172 in Pembrokeshire, Wales, United Kingdom to Richard de Clare, 2nd Earl of Pembroke (1130-1176) and Aoife MacMurrough (1145-1188) and died 1220 Pembrokeshire, Wales, United Kingdom of unspecified causes. She married William Marshal, 1st Earl of Pembroke (1146-1219) August 1189 JL .
Children
| Name | Birth | Death | Joined with |
| William Marshal, 2nd Earl of Pembroke (1190-1231) | 1190 | 6 April 1231 | Alice de Betun (c1202-c1216) Eleanor of England (1215-1275) |
| Richard Marshal, 3rd Earl of Pembroke (1191-1234) | |||
| Maud Marshal (1192-1248) | 1192 | 27 March 1248 | Hugh Bigod (c1182-1225) William de Warenne (1166-1240) |
| Gilbert Marshal, 4th Earl of Pembroke (1197-1241) | |||
| Walter Marshal, 5th Earl of Pembroke (c1199-1245) | |||
| Isabel Marshal (1200-1240) | 9 October 1200 | 17 January 1240 | Gilbert de Clare, 5th Earl of Hertford (1180-1230) Richard Plantagenet, 1st Earl of Cornwall (1209-1272) |
| Sibyl Marshal (c1201-1245) | 1209 | 1238 | William de Ferrers, 5th Earl of Derby (c1193-1254) |
| Eva Marshal (1203-1246) | 1203 Pembroke Castle, Pembrokeshire, Wales, United Kingdom | 1246 | William de Braose, 10th Baron Abergavenny (c1197-1230) |
| Anselm Marshal, 6th Earl of Pembroke (c1208-1245) | |||
| Joan Marshal (1210-1234) | |||
Footnotes (including sources)
| ‡ General |