Facts and Events
Gilbert de Clare, born abt 1180, had a brother Richard/Roger and a sister Matilda. He was a Magna Charta Surety. At age 38, he became the sole heir to the Clare and Gloucester estates and title. By a remarkable series of fortuitous marriages and quick deaths, the Clares were left in 1217 in possession of an inheritance which in terms of social prestige, potential revenues, knights' fees, and a lasting position of great importance among the marcher lords of Wales. They were probably the most successful family in developing their lands and power during the 12th century and in many ways the most powerful noble family in 13th century. By 1317, however, the male line of Clares became extinct and the inheritance was partitioned. Between 1217 and 1317 there were four Clare generations.
Gilbert de CLARE assumed the title of earl of Gloucester and Hertford and was charged L350 relief for the honors of Clare, Gloucester, St. Hilary and his half of the old Giffard barony. He controlled some 456 knights fees, far more than any other, and it did not include some 50 fees in Glamorgan and Gwynllwg.
In June 1202 he was entrusted with the lands of Harfleur and Mostrevilliers. He was one of the Barons still opposing the arbitrary proceedings of the Crown. He championed Louis the Dauphin, fighting at Lincoln under the Baronial banner, and was taken prisoner by William Marshall, whose daughter he later married. He led an army against the Welsh in 1228 and captured Morgan Gam, who was released the next year. After an engagement in Brittany, he died on his return at Penrose in that Duchy, 25 October 1230. His body was conveyed by way of Plymouth and Cranbourn to Tewkesbury. He was buried there before the High Altar 10 November 1230. He married Isabella, sister of William Marshall, the Surety, and daughter of William Marshall, the Protector, on 9 October 1217. She died 17 January 1239/40.
For more information, see the EN Wikipedia article Gilbert de Clare, 4th Earl of Hertford.