Isolde de Mortimer was born circa 1275 in England, United Kingdom to Edmund Mortimer, 2nd Baron Mortimer (1251-1304) and Margaret de Fiennes (aft1269-1333) and died circa 1338 England, United Kingdom of unspecified causes. She married Hugh de Audley (c1274-1326) 1288 JL .
Children
| Name | Birth | Death | Joined with |
| Elizabeth de Audley (c1289-c1345) | 1289 Bostock, Cheshire, England, United Kingdom | 1345 Cheshire, England, United Kingdom | William de Bostock (c1288-c1340) |
| Hugh de Audley, 1st Earl of Gloucester (c1291-1347) | 1291 Oxfordshire, England, United Kingdom | 10 November 1347 France | Margaret de Clare (1293-1342) |
| Nicholas de Audley (c1290) | |||
| James de Audley (c1292-aft1333) | |||
| Alice de Audley (c1300-c1375) | 1300 | 11 January 1374 Greystoke, Northumberland, England, United Kingdom | Ralph, 3rd Lord of Greystoke (1299-1323) Ralph Neville, 2nd Baron Neville of Raby (c1291-1367) |