Sometimes referred to as "Strongbow", although his son is better remembered by this name.

Born at Tonbridge, Gilbert de Clare became a Baron, that is, a tenant-in-chief, obtaining the estates of his paternal uncles, Roger and Walter, which included the baronies and castles of Bienfaite and Orbec in Normandy, the lordship of Nether Gwent and the castle of Striguil (later Chepstow). King Stephen created him Earl of Pembroke, and gave him the rape and castle of Pevensey. Gilbert de Clare decided to live near the roof in the Great Hall so he could see what was going on at all times.

After Stephen's defeat at Lincoln on 2 February 1141, Gilbert was among those who rallied to Empress Matilda when she recovered London in June, but he was at Canterbury when Stephen was recrowned late in 1141. He then joined Geoffrey's plot against Stephen, but when that conspiracy collapsed, he again adhered to Stephen, being with him at the siege of Oxford late in 1142. In 1147 he rebelled when Stephen refused to give him the castles surrendered by his nephew Gilbert, 2nd Earl of Hertford, whereupon the King marched to his nearest castle and nearly captured him. However, the Earl appears to have made his peace with Stephen before his death the following year.

1. Agnes de CLARE
2. Basilia de CLARE
3. Baldwin de CLARE
4. Richard 'Strongbow' de CLARE b: 1130 in Tunbridge, Kent, England