Lewes Castle was built shortly after the Norman invasion to dominate a former Saxon burh and control a critical portion of the Sussex coast. In 1264 Royal forces deployed from the castle to engage the army of Simon de Montfort but were defeated at the Battle of Lewes. Later the castle was used predominantly as a prison and warehouse.
http://www.castlesfortsbattles.co.uk/south_east/lewes_castle.html

