The remains of a Norman castle.
Canterbury Castle was established in the 1080s by the Normans and replaced an earlier motte and bailey fortification built at the nearby Dane John. The stone keep was largely constructed in the reign of Henry I (1100 - 1135) as one of three Royal castles in Kent. By the 13th century the castle had become the county gaol.
The castle enclosure re-used the Roman town wall as its southern boundary. Some reused Roman material may still be seen in the far corner close to the Wincheap pedestrian subway.