Gilbert de Clare was the son of Richard Fitz Gilbert, was born in 1066. He later married Adeliz, the daughter of Hugh of Clermont.
Gilbert, like his father, took part in the rebellion against William Rufus in 1088. After a two day siege at Tonbridge Castle, the Clare family was forced to surrender to the king's forces. The was punished by having his castle and the town of Tonbridge burnt to the ground. Richard Fitz Gilbert was also forced to live in a monastery where he died three years later.
Gilbert was allowed to keep the family estates and in June 1095 fought with William Rufus against the Scots. He is also believed to have taken part in William's military campaigns in Wales and Normandy.
On 2nd August 1100, William Rufus went hunting at Brockenhurst in the New Forest. Gilbert and his younger brother, Roger of Clare, were with the king. Another man in the hunting party was Walter Tirel, who was married to Richard de Clare's daughter, Adelize. Also present was William Rufus' younger brother Henry. During the hunt, Walter Tirel fired an arrow at a stag. The arrow missed the animal and hit William Rufus in the chest. Within a few minutes the king was dead. Tirel jumped on his horse and made off at great speed. He escaped to France and never returned again to England.
Most people expected Robert Curthose to become king. However, his younger brother Henry Beauclerk decided to take quick action to gain the throne. As soon as he realised William Rufus was dead, Henry rushed to Winchester where the government's money was kept. After gaining control of the treasury, Henry declared he was the new king. Supported by the Clares, Henry was crowned king on 5th August. Although Robert threatened to invade England, he eventually agreed to do a deal with Henry. In return for an annual payment of £2,000, Robert accepted Henry as king of England.
King Henry I generously rewarded the Clare family for their loyalty. Although Walter Tirel never returned to England, his son was allowed to keep his father's estates. Some people suspected that Henry and the Clare family had planned the murder of William Rufus. Others accepted that William Rufus' death was an accident. Whatever the truth of the matter, the Clare family obtained considerable benefit from the death of William Rufus.
In 1107 Gilbert led an army into Wales. After defeating Cadogan King Henry I allowed him to take control of Cardigan. It is also believed that Gilbert became lord marcher of Striguil.
Gilbert de Clare was the father of three sons, Richard, Earl of Hertford, Gilbert, Earl of Pembroke and Walter de Clare. He also had a daughter, Rohaise, who married Baderon de Monmouth. Gilbert de Clare died in 1115.
Gilbert and Roger, sons of Richard de Clare, who were present at Brockenhurst when the King was killed... were brothers-in-law of Walter Tirel... Richard, another brother-in-law, was promptly selected to be Abbot of Ely by King Henry I, who further gave the see of Winchester to William Giffard, another member of the same powerful family circle.
Historians... have hinted that barons... perhaps led by the Clares... had arranged William's death. But there is not a shred of good evidence and the theory merely avoids the obvious. Hunting accidents were, after all, not uncommon.