Isabel de Clare 1
- Born: 2 Nov 1226
- Marriage (1): Robert de Brus 5th Lord of Annandale on 12 May 1240
- Died: 10 Jul 1264 at age 37
Other names for Isabel were Isabella of Gloucester and Hertford and Isobel de Clare.
Mother of Robert the Bruce (Robert de Brus, 6th Lord of Annandale).
From Wikipedia - Isabella of Gloucester and Hertford :
Isabella of Gloucester and Hertford (2 November 1226- 10 July 1264), was the daughter of Gilbert de Clare, 5th Earl of Hertford and 1st Earl of Gloucester and Isabel Marshal . She is also known as Isabel de Clare...
Isabella's maternal grandparents were William Marshal, 1st Earl of Pembroke and his wife Isabel de Clare, 4th Countess of Pembroke . Isabella's paternal grandparents were Richard de Clare, 4th Earl of Hertford and Amice FitzRobert . 
Isabella was the four of six children, her brother was Richard de Clare, 6th Earl of Hertford . Her sister, Amice de Clare married Baldwin de Redvers, 6th Earl of Devon and was mother of Baldwin de Redvers, 7th Earl of Devon and Isabella de Fortibus, Countess of Devon .
Isabella married on 12 May 1240  to Robert de Brus, 5th Lord of Annandale , Isabella brought to him, the village of Ripe, in Sussex . Her husband was a candidate to become King of Scotland , after the death of the young Margaret, Maid of Norway . Her husband did not however succeed, Robert's rival, John Balliol was elected King of Scotland in 1292. 
Robert and Isabella had at least three children:
1. Isabella Bruce (b. 1249 - c1284), married (as his first wife) Sir John FitzMarmaduke, Knt., of Horden, Eighton, Lamesley, Ravensholm, and Silksworth, county Durham, Sheriff of North Durham, and Joint Warden beyond the Scottish Sea between the Forth and Orkney . He fought on the English side at the Battle of Falkirk , July 22 , 1298 , and was present at the Siege of Caerlaverock Castle in 1300. In 1307 he was commanded to assist the Earl of Richmond in expelling Robert de Brus and the Scottish rebels from Galloway . In 1309 his armour and provisions in a vessel bound for Perth were arrested off Great Yarmouth . He was governor of St. John's Town (Perth) in 1310 until his death. Isabel was buried at Easington , county Durham.
2. Robert VI the Bruce, Earl of Carrick (1253 - 1304)
3. Constance Bruce (b. 1251), married Sir William Scot de Calverley and had daughter, Clarissa Scott (m. Sir John Fairfax)
John Balliol's time as King of Scotland did not last long, he died in 1314. Isabella's grandson, Robert the Bruce became King of Scotland . Isabella did not however get to see this day, she died in 1264, aged thirty seven. Her husband married a second time, to Christina de Ireby , this marriage produced at least one daughter, Christina.
Isabel married Robert de Brus 5th Lord of Annandale on 12 May 1240. (Robert de Brus 5th Lord of Annandale was born about 1215, died on 31 Mar 1295 and was buried in Gisborough Priory, Guisborough, North Yorkshire, England.)