[1] He was a relative of Walter Giffard and uncle of William of Bitton II, his two successors in the office of Bishop of Bath and Wells.
[2] He was also uncle of Thomas of Bitton, precentor, archdeacon and dean of Wells,[3] and Bishop of Exeter.
[6] In 1251 he signed the proclamation of excommunication against any who did not observe the clauses of Magna Carta dealing with ecclesiastical rights.
In 1257, the bishops made specific reference to William's conflict with the Abbot of Glastonbury in their communications with the king.
However, he lost a long fight with the abbot of Glastonbury Roger Forde over the right of the bishop to visit and regulate the affairs of Glastonbury Abbey, and by the end of his term as bishop, the abbey was independent of the diocese in all but name.