A horseshoe shaped earthwork and low wall are located around the southern side of the Church of St Mary and the Roman tower. The first wall here was constructed in the reign of King John (1199-1216), though the massive earthwork which occupies this space today is a later replacement of an earlier earthwork, built after the great siege, in around 1227. As indicated by documentary and archaeological evidence this was originally topped with a timber palisade which was replaced by a stone wall in 1256. (location accurate to the nearest 1m based on available information)