This tower is part of Henry III’s curtain wall around the fortress. It was built in 1238-41 and this ground floor room is the only original part. The rest was rebuilt in the 19th century.

There were originally three arrow loops through which archers could shoot at attackers. Only one survives. Afterwards, the room was used for weapons' storage and domestic purposes. Here you can see two stone cupboards and, next to them, the entrance to a stair turret with a garderobe (toilet) underneath.

Beneath its floor lie the remains of the Roman city wall of about 200 AD. It was destroyed when Henry III expanded the fortress ten centuries later.