William de Ferrers 3rd Earl of Derby 1 2 3 4
- Born: Abt 1140
- Christened: <Tutbury Castle, Tutbury, Staffordshire, England>
- Marriage (1): Sibyl de Braose about 1174 in Sussex, England
- Died: Bef 21 Oct 1190, Acre, Palestine (Israel)
Another name for William was William de Ferrières 3rd Earl of Derby.
Seigneur of Ferrieres-Saint-Hilaire and lord of Oakham, Rutland.
Source: Ancestral Roots of Certain American Colonists Who Came to America before 1700 by Frederick Lewis Weis and Walter Lee Sheppard, Jr, ed. by William R. Beall & Kaleen E. Beall (Baltimore, 2008), line 132C-28 (Roger de Mortimer)
From Wikipedia - William de Ferrers, 3rd Earl of Derby :
William I de Ferrers, 3rd Earl of Derby (died 1190) was a 12th century English Earl who resided in Tutbury Castle in Staffordshire and was head of a family which controlled a large part of Derbyshire known as Duffield Frith . He was also a Knight Templar . 
William was the son of Robert de Ferrers, 2nd Earl of Derby and his wife, Margaret Peverel . He succeeded his father as Earl of Derby in 1162. He was married to Sybil, the daughter of William de Braose, 3rd Lord of Bramber and Bertha of Hereford .
William de Ferrers was one of the earls who joined the rebellion against King Henry II of England led by Henry's eldest son, Henry the Younger , in the Revolt of 1173-1174 , sacking the town of Nottingham . Robert de Ferrers II, his father, had supported Stephen of England and, although Henry II had accepted him at court, he had denied the title of earl of Derby to him and his son.  In addition, William had a grudge against Henry because he believed he should have inherited the lands of Peveril Castle through his mother. These, King Henry had previously confiscated in 1155 when William Peverel fell into disfavour.
With the failure of the revolt, de Ferrers was taken prisoner by King Henry, at Northampton on the 31 July 1174, along with the King of Scots and the earls of Chester and Lincoln, along with a number of his Derbyshire underlings and was held at Caen . He was deprived of his castles at Tutbury and Duffield and both were put out of commission (and possibly Pilsbury .) In addition to defray 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 joined the Third Crusade and died at the Siege of Acre in 1190. 
Was killed during the Siege of Acre.
William married Sibyl de Braose, daughter of William de Braose 3rd Lord of Bramber and Bertha de Pitres of Hereford, about 1174 in Sussex, England. (Sibyl de Braose was born about 1157 in Bramber, Sussex, England and died after 5 Feb 1228 in England.)