William was the first-born son of
William FitzOsbern, a
companion of
Duke William II of
Normandy during his
conquest of
England in 1066. Following the conquest, the father became the 1st
earl of
Hereford. Upon his father's death in 1071 he inherited extensive estates in central Normandy including the
lordship of
Breteuil and
Pacy in
Eure. During the turbulent period following the death of the new English king in 1087, his sons
Robert Curthose and
William Rufus contested control over Normandy and England and their
vassals waged numerous local wars against one another. In November 1090, he aided duke Robert to suppress the
Rouen Riot and captured William, son of a wealthy burgher called Ansgar, for ransom. In the conflict between
William,
count of
Evreux, and his half-brother
Raoul II, lord of
Conches, over their wives' insults towards one another, William of Breteuil and
Richard of Montfort allied with Count William and joined his invasion of Raoul's lands in November 1091. Lord William's capture in 1092 doomed Count William's cause. His
ransom amounted to 3000
livres (about of
fine silver) and the recognition of Raoul's son Roger as heir to both Lord William and Count William. Roger, however, died young and the issue became moot. Lord William was present at the hunt in the
New Forest (probably near
Brockenhurst) where
William Rufus was killed by an arrow through his lung. He attempted to defend the
crown jewels in the
Winchester treasury against
Prince Henry in deference to the claims of his duke Robert but was forced to yield. Henry, supported by other nobles against his "foreign" brother, was crowned king shortly afterwards at London. William of Breteuil was married to Adeline of
Montfort William died at
Bec Abbey in Normandy on 12 January 1103. He was succeeded by his son Eustace in preference to his legal heirs William of Gael and Reginald of Grancey as his Norman subjects "chose to be ruled by a fellow countryman who was a bastard rather than by a legitimate
Breton or
Burgundian". ==References==