William Marshal, 4th Earl of Pembroke, was probably born in 1146. He was foremost among King John's loyalists and was one of the chief mediators in the years leading up to the granting of Magna Carta in 1215.
Following King John's sudden death in 1216, he was appointed to rule England during the minority of Henry III, who was only nine years old when he came to the throne. He was responsible for issuing two revised versions of Magna Carta in 1216 and 1217, to secure baronial support for the young king's reign.
He died in 1219 and was buried in the Temple, London.