From Wikipedia en.wikipedia.org/wiki/Christchurch_Castle
Christchurch Castle is located in Christchurch, Dorset, England
It originated as Norman motte and bailey castle raised around 1100 by Richard de Redvers, cousin of Henry I. A great tower was built later probably about 1300.
The castle saw military activity in 1147 during the war between King Stephen and the Empress Matilda. It was also involved in the Civil War when it was initially a Royalist castle. As a result of this it was slighted in about 1652.
The castle is now in ruins. A couple of the keep walls remain, surrounded by a rectangular moat. Nearby is a domestic Norman dwelling, known as the Constable's House, which was built within the original castle bailey in 1160.