William IX
William IX, Count of Poitiers.jpg
William IX, from an early 14th century genealogical tree
British Library Royal MS 14 B VI.
Count of Poitiers
PredecessorHenry and Eleanor
SuccessorHenry and Eleanor
Born17 August 1153
Normandy, France
Died1156 (aged 2–3)
Wallingford Castle, Berkshire
Reading Abbey, Berkshire
HousePlantagenet / Angevin
FatherHenry II, King of England
MotherEleanor, Duchess of Aquitaine

William (17 August 1153 – 1156) was the first son of King Henry II of England and Duchess Eleanor of Aquitaine.[1] He was born in Normandy on the same day that his father's rival, Eustace IV of Boulogne, died.

William either died aged 3 on 2 December 1156,[2][3] or aged 2 in April 1156.[4] This was due to a seizure at Wallingford Castle, and he was buried in Reading Abbey at the feet of his great-grandfather Henry I.[4]

At the time of his death, William was reigning as Count of Poitiers, as his mother had ceded the county to him. For centuries, the dukes of Aquitaine had held this as one of their minor titles, so it had passed to Eleanor from her father; giving it to her son was effectively a revival of the title, separating it from the duchy. Some authorities say he also held the title of "Archbishop of York", but this is probably an error. His half-brother Geoffrey (died 1212), who was born a year before William, later held that office, causing the confusion.


  1. ^ Warren 1995, p. 137.
  2. ^ Huscroft 2016, p. 110.
  3. ^ Strickland 2007, p. 184.
  4. ^ a b Baxter 2016, p. 77.


William IX, Count of Poitiers House of PlantagenetBorn: 17 August 1153 Died: April 1156 Regnal titles Preceded byHenry and Eleanor Count of Poitiers 1153–1156 Succeeded byHenry and Eleanor