Corfe Castle is a fortification standing above the village of the same name in the English county of Dorset. Built by William the Conqueror, the castle dates back to the 11th century and commands a gap in the Purbeck Hills on the route between Wareham and Swanage. The first phase was one of the earliest castles in England to be built using stone when the majority were built with earth and timber. Corfe Castle underwent major structural changes in the 12th and 13th centuries. Reference: Wikipedia