arnham Castle consists of the remains of a motte and bailey castle that would have had a large square tower on top. The castle is situated on a steep hill giving both protection from attack and excellent views. A well in the centre of the mound descends to ground level and below to the source of water that kept the castle supplied. The area is associated with the Bishops of Winchester and it was Henry, the brother of King Stephen who was responsible for the creation of the castle in the first half of the twelfth century. After the Civil War between Matilda and Stephen, the castle was dismantled, but was later rebuilt. The rebuilding work saw the mound surrounded by a stone wall and the edges filled in to form what is known as a 'shell keep'. The keep had one entrance tower which had a drawbridge and a pit beneath. The shell keep also had four towers or turrets around the edge.