The Rings is a Norman earth and timber ringwork and bailey fortress, founded by King Stephen. Standing on a low chalk ridge, the siege castle was probably built during the Anarchy in 1139, when Stephen unsuccessfully besieged Corfe Castle. The circular ringwork with its large earthen rampart, is encased by ditch and within the south-east quadrant is a platform, which is thought to represent an English Civil War battery emplacement. The adjoining south-eastern bailey is encased by the remains of a bank and ditch and an entrance at its southern end appears to be original. Traditionally a Parliamentarian battery was sited here in the 17th century Civil War and the tithe map of 1844 called the site 'Cromwell's Battery'. On the north-west side of the ringwork, the rampart and ditch are cut by the road and the southern end of the bailey is reduced and levelled by ploughing.