The Norman baron, Eudo Dapifer, built Colchester Castle, 1075 - 1080, around the podium of the Roman Temple of Claudius, creating the largest Norman keep in Britain.

Colchester had been the first Roman capital of Britain, and the castle is largely built from materials salvaged from the surrounding Roman remains. The castle was partially demolished in 1683, which has led to much speculation about its original height, with the addition of another two storeys being the most popular theory.

The castle now houses an award winning museum, with many exhibits about the Roman history of Colchester. The Roman vaults and other parts of the castle not freely open to the public can be seen on guided tours which are available throughout the day.