EUSTACE IV. (d. 1153) became the heir-apparent to his father's possessions by the death of an elder brother before 1135. In 1137 he did homage for Normandy to Louis VII. of France, whose sister, Constance, he subsequently married. Eustace was knighted in I147, and in 1151 joined Louis in an abortive raid upon Normandy, which had accepted the title of the empress Matilda, and was now defended by her husband, Geoffrey of An jou. At a council held in London on April 6, 1152 Stephen induced a small number of barons to do homage to Eustace as their future king; but the primate, Theobald, and the other bishops declined to perform the coronation ceremony on the ground that the Roman curia had declared against the claim of Eustace, whose death in 1153 opened up the possibility of a peaceful settlement between Stephen and his rival, the young Henry of Anjou.
See Sir James Ramsay, Foundations of England, vol. ii. (1898) ; J. M. Lappenberg, History of England under the Norman Kings (trans. B. Thorpe, 1857) ; and Freeman's Hist. of the Norman Conquest