Eustace IV, Count of Boulogne Eustace IV, Count of Boulogne Eustace IV (c. 1127–1135 – 17 August 1153), Count of Boulogne, was the eldest son of King Stephen of England and Countess Matilda I of Boulogne. When his father seized the English throne on Henry I's death in 1135, he became heir apparent to the English throne. Upon his mother's death in 1152 he inherited the county of Boulogne and other estates. Eustace was first mentioned in one of his parents' charters dated no later than August 1131. As heir to the English throne in 1137, he did homage for Normandy to Louis VII of
The Anarchy the spoils. William's son Henry I seized power after the death of his elder brother William Rufus and subsequently invaded and captured the Duchy of Normandy, controlled by his eldest brother Robert Curthose, defeating Robert's army at the Battle of Tinchebray. Henry intended for his lands to be inherited by his only legitimate son, seventeen-year-old William Adelin. In 1120, the political landscape changed dramatically when the "White Ship" sank en route from Barfleur in Normandy to England; around three hundred passengers died, including Adelin. With Adelin dead, the inheritance to the English throne was thrown into doubt. Rules of succession