Colchester Castle is the largest stone keep ever built in Britain and is the largest remaining in Europe. It is built on the site of the earlier Roman temple dedicated to Claudius (AD 54-60).
Construction of the castle was began on the order of William the Conqueror and it was designed by Gundulf, Archbishop of Rochester. Building began between 1069 and 1076 under the supervision of Eudo Dapifer, who was later to become the steward of the castle upon its completion. The castle was completed by around 1100, construction had been delayed due to the threat of Viking invasion.
Over the centuries the castle has been used for many purposes, including as a prison and by grain merchants. The castle is now home to a local museum charting the history of the local area.