William was the son of Robert de Ferrers, 2nd Earl of Derby, and his wife, Margaret Peverel.
He was married to Sybil, the daughter of William de Braose, 3rd Lord of Bramber, and Bertha of Hereford.
[1] In addition, William had a grudge against Henry because he believed he should have inherited the lands of Peveril Castle through his mother.
In addition to defraying the costs of the war, Henry levied a so-called "forest fine" of 200 marks.
He seems to have afterwards regained the confidence of Henry II, and he showed his fidelity to the next sovereign, King Richard I, by accompanying him in his expedition to the Holy Land, and joining the Third Crusade and died at the Siege of Acre in 1190.