Isabella Brienne de Beaumont was born circa 1320 to Henry Beaumont (c1255-1339) and Alice Comyn (bef1296-bef1349) and died 1361 of unspecified causes. She married Henry of Grosmont, 1st Duke of Lancaster (c1310-1361) . Charlemagne (747-814)/s, Henry II of England (1133-1189)/s, Hugh Capet (c940-996)/s, William I of England (1027-1087)/s.
|Offspring of Isabella de Beaumont and Henry of Grosmont, 1st Duke of Lancaster (c1310-1361)|
|Maud of Lancaster (1339-1362)||4 April 1339||10 April 1362||Ralph Stafford Ralph Stafford William von Wittelsbach (1330-1389)|
|Blanche of Lancaster (1345-1369)||25 March 1345||12 September 1369 Bolingbroke Castle||John of Gaunt, 1st Duke of Lancaster (1340-1399)|