| 6th Baron of Thirsk William de Mowbray | |
| B: | 1173 |
| Thirsk Castle, Thirsk, Yorkshire, England | |
| D: | 1224 |
| Isle of Axholme, Epworth, Lincolnshire, England | |
| Mabel de Clare | |
| B: | Abt 1150 |
| Tonbridge Castle, Tonbridge, Kent, England | |
| D: | 1204 |
| 4th Earl of Hertford Gilbert de Clare | |
| B: | Abt 1180 |
| Hertford, Hertfordshire, England | |
| D: | 25 Oct 1230 |
| Brittany, France | |
| Countess Isabel Marshal | |
| B: | 09 Oct 1200 |
| Pembroke Castle, Pembrokeshire,Wales | |
| M: | 09 Oct 1217 |
| Tewkesbury Abbey, Tewkesbury, Gloucestershire, England | |
| D: | 17 Jan 1240 |
| Berkhamsted Castle, Berkhamsted, Hertfordshire, England | |
| 3rd Earl of Hereford Richard de Clare | |
| B: | Abt 1153 |
| Tonbridge Castle, Tonbridge, Kent, England | |
| D: | 1217 |
| 2nd Earl of Hertford Roger de Clare | |
| B: | 1116 |
| Tonbridge Castle, Tonbridge, Kent, England | |
| D: | 1173 |
| Oxfordshire, England | |
