Isabel Bigod was born circa 1212 in Thetford to Hugh Bigod, 3rd Earl of Norfolk (c1182-1225) and Maud Marshal (1192-1248) and died 1252 of unspecified causes. She married Gilbert de Lacy (?-1234) . She married John Fitzgeoffrey (c1205-1258) .
Children
| Name | Birth | Death | Joined with |
| Walter de Lacy (?-1241) | |||
| Margery de Lacy (c1226-1256) | 1226 | 1256 | John de Verdun (c1226-1274) |
| Maud de Lacy (c1233-1303) | |||
| Name | Birth | Death | Joined with |
| John FitzJohn (-1275) | |||
| Richard FitzJohn (-1297) | |||
| Maud FitzJohn (-1301) | |||
| Isabel FitzJohn (-) | |||
| Aveline FitzJohn (c1244-1274) | 1244 | 1274 | Walter de Burgh (c1230-1271) |
| Joan FitzJohn (1245-1303) | 1245 Shere | 1303 | Theobald Butler (c1242-1285) |
Footnotes (including sources)