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 of the senior clergy in England and Normandy. Henry's only legitimate son and heir, William Adelin, drowned in the "White Ship" disaster of 1120, throwing the royal succession into doubt. Henry took a second wife, Adeliza of Louvain, in the hope of having another son, but their marriage was childless. In response to this, Henry declared his daughter, Empress Matilda, his heir and married her to Geoffrey of Anjou. The relationship between Henry and the couple became strained, and fighting broke out along the border with Anjou. Henry died on 1 December 1135 after a week of illness. Despite his