William de Fitz Osbern seigner de Bréteuil, Earl of Hereford
- Born: Normandy, France
- Marriage (1): Adelise de Toeni 141
- Marriage (2): Richilde Comtesse de Hainault Shortly before 1071 160
- Died: 1071, Battle of Cassel, Normandy, France 141
- Buried: 1071, Abbey of Cormeilles 141
Another name for William was William Earl of Hereford.
From The Companions of William the Conqueror:
"William Fitz Osbern claims precedence as the nearest personal friend of the Conqueror, and the chief officer of his household." 197
Noted events in his life were:
• Background Information. 141
William Fitz Osbern, Seigneur de Breteuil, son and heir of Osbern, steward of Normandy, by Emma, daughter of Ralph, Count of Ivry, was to take a leading part in the events leading up to and in the Battle of Hastings. He was thereafter rewarded with great estates in England, namely, the Isle of Wight and the County of Hereford, becoming Earl of Hereford. According to the Domesday Book he divided Herefordshire into "casteleries," and attracted many knights to his service by liberal pay, even making a special law that none should pay for any offence more than seven shillings.
William was in command of the army during William's absence in 1067, and his representative in the north. In 1068 he was in Normandy with the Duke, and in 1068/9 was governor of York. He is credited, in 1070, for searching the monasteries in England for treasure deposited there. In 1070, or early in 1071, he was sent to Normandy to assist Queen Maud in the administration of the Duchy, and so became involved in the troubles in Flanders, where the Queen was supporting her nephew Arnolf's succession to his grandfather, Baldwin, Count of Flanders. The Earl joined Philip of France with ten knights only and went off to Flanders, where he was killed, 18 February 1070/1.
He married, 1st, Adelise, daughter of Roger de Toeni, standard-bearer of Normandy. She was burried in the Abbey of Lire, which her husband had founded. He married, 2nd, shortly before his death, Richilde, widow of Baldwin (VI), Count of Flanders. The Earl died as aforesaid in 1071, and was buried in the Abbey of Cormeilles, which he had also founded. His widow appears to have died 15 March 1086/7. She was buried with her 2nd husband in the Abbey of Hasnon, which they had founded.
~Cokayne's Complete Peerage, 2nd Edition, (Hereford), Vol. VI, pp. 447-449
• Web Reference: William Fitz Osbern Castle builder.
William married Adelise de Toeni, daughter of Roger I "the Spaniard" de Toeni seigneur de Toeni et Conches and Godehut.141 (Adelise de Toeni was buried in Abbey of Lire 141.)