The original castle was built on a mound above the River Ehen on the site of a Danish fort following the conquest of Cumberland in 1092 by William II of England. The present castle was built by William Meschin, who founded the castle between 1120 and 1135. Further additions were made in the 13th century. It eventually fell into disuse and became the ruin it is today. The castle is of Motte-and-bailey design.