Fulk FitzWarin at the time of his death in 1197. Whittington Castle lies on the English side of Offa's Dyke, which during the Norman era and before was the border between England and Wales. The site was fortified as a castle by William Peverel in 1138, in support of Empress Matilda, the daughter of King Henry I (1100–1135), in her struggle (known as The Anarchy) for the throne against King Stephen (1135–1154), grandson of William the Conqueror. In the late 1140s the lordship of Whittington, like Oswestry and Overton ceased to be part of England and became part of the Kingdom of
Henry I of England December. The Empress Matilda did not give up her claim to England and Normandy, leading to the prolonged civil war known as the Anarchy between 1135 and 1153. Historians have drawn on a range of sources on Henry, including the accounts of chroniclers; other documentary evidence, including early pipe rolls; and surviving buildings and architecture. The three main chroniclers to describe the events of Henry's life were William of Malmesbury, Orderic Vitalis, and Henry of Huntingdon, but each incorporated extensive social and moral commentary into their accounts and borrowed a range of literary devices and stereotypical events from other popular