Whittington lies on the English side of Offa's Dyke, which in this area was the Norman boundary between England and Wales. The castle of Whittington may have begun as a Norman manor house, although there is no evidence for this. The site was fortified as a castle for William Peverel, in 1138, in support of Empress Matilda, the daughter of Henry I against King Stephen, nephew of King Henry I, and claimant to the throne during The Anarchy. In 1149, the lordship of Whittington, like Oswestry, was annexed by Madog ap Maredudd and became part of the Kingdom of Powys until Madog's death in 1160.