Historically the earliest form of the castle is credited as Norman construction. However, it has continuously been added to and rebuilt many times, reflecting portions of architecture ranging throughout the medieval era.
The castle is perched upon a large knob of volcanic basalt, and is overlooking the only two viable landing beaches on the island. It dominates the landscape and with clear lines-of-sight make it a formidable structure.
During the Great War, the castle was used as a prison for political prisoners. It was closed in 1933, due to excessive cost of upkeep and is currently uninhabited.