Richard de Clare, the son of Roger of Clare, was born in 1153. On the death of his father in 1173 he became the 6th Earl of Clare and the 4th Earl of Hertford. He married Amicia, the daughter of the Earl of Gloucester. In 1183 Richard de Clare obtained control of Glamorgan, the largest and the most important marcher lordship in Wales.
In 1200, King John became involved in a long-drawn out war with France. This war was expensive and John was forced to introduce new taxes to pay for his army. This created a great deal of resentment in England, and John's position was not helped when, in 1205, the king's army lost control of Normandy, Brittany, Anjou and Maine.
In 1215, King John made another desperate attempt to gain control of his lost territory in France. Once again he was defeated and was forced to pay £40,000 to obtain a truce. When John tried to obtain this money by imposing yet another tax, the barons rebelled.
Richard de Clare was one of the leaders of the rebellion. Few barons remained loyal, and in most areas of the country, John had very little support. John had no chance of victory and on 15th June, 1215, at Runnymede in Surrey, he was forced to accept the peace terms of those who had successfully fought against him.
The document the king was obliged to sign was the Magna Carta. In this charter the king made a long list of promises, including no new taxes without the support of his barons, a reduction in the power of his sheriffs and the right of a fair trial for all freemen.
The barons had doubts whether King John could be trusted to keep his word. A small group of barons were given the task of making sure that John kept the promises he had made in the Magna Carta. Two of the barons chosen were Richard de Clare and his son Gilbert de Clare.
Soon after he signed the charter the king appealed to Pope Innocent III for help. The pope was concerned about this rebellion and decided to excommunicate the barons who had fought against their king. The pope also provided money to help King John recruit foreign mercenaries to fight against his disloyal barons. The civil war resumed. One of King John's main targets was Richard of Clare and in November, 1215, his troops seized his castle at Tonbridge.
Richard de Clare died in 1217.