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
Succession of Henry IV of France view, Henry remained a heretic and, therefore, an usurper on the throne of France. On the death of King Henry III of France, who had no son, the crown passed to Henry IV, in application of Salic law, because Henry was the descendant of the eldest surviving male line of the Capetian dynasty. Henry IV's descent in the male line from Louis IX of France. Succession of Henry IV of France Henry IV of France's succession to the throne in 1589 was followed by a four-year war of succession to establish his legitimacy. This was part of the French Wars