In 1173, the earl took the King's part against his sons, but, thereafter, he appears to have fallen under suspicion, given that the following year he submitted to the King and in 1175 surrendered to him
Bristol Castle. Because his only son and heir, Robert, died in 1166, Earl William made John, the younger son of King
Henry II, heir to his earldom, in conformity with the King's promise that John should marry one of the Earl's daughters, if the Church would allow it, they being related in the third degree. Earl William was present in March 1177 when the King arbitrated between the Kings of Castile and Navarre, and, in 1178, he witnessed Henry's charter to Waltham Abbey. But, during the King's struggles with his sons, when he imprisoned a number of magnates of whose loyalty he was doubtful, Earl William was among them. ==Family and children==