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
Henry of Bohemia appointed his brother-in-law regent. Upon Wenceslaus' assassination on August 4, the Přemyslids became extinct in the male line and Henry was elected his successor by the Bohemian nobility—against the will of his former ally King Albert I of Germany, who intended to install his eldest son Rudolf of Habsburg on the Bohemian throne. King Albert's troops immediately campaigned Bohemia, besieged Prague Castle and deposed Henry, who had to yield to their superior forces. Nevertheless, Rudolf of Habsburg (mocked as "král kaše", "King Porridge") was never accepted by the Bohemian nobles, and after his sudden death on 4 July 1307, Henry