In August 1189 Richard I arranged the marriage of Isabel, de Clare's granddaughter, to William Marshal who received both the castle and the title, Earl of Pembroke. He had the castle rebuilt in stone and established the great keep at the same time. Marshal was succeeded in turn by each of his five sons. His third son, Gilbert Marshal, was responsible for enlarging and further strengthening the castle between 1234 and 1241. All of Marshal's sons died childless. In 1247, the castle was inherited by William de Valence (a half-brother of Henry III), who had become Earl of Pembroke through his marriage to Joan de Munchensi, William Marshal's granddaughter.