Old Sarum

Image: Model of 12th century Old Sarum - source Wikipedia

Old Sarum lies on the eastern boundary of Stratford sub Castle. Its hill has been the site of an iron-age hillfort, a Norman castle and a cathedral. The castle led to our settlement becoming known as Stratford under the Castle, (amongst other variations)

see name origin

North of Salisbury the ground rises rapidly from the west bank of the Bourne, and the high land thrusts out a narrow neck ending in a spur towards the Avon. On the north, west and south the spur falls away in steep banks: at the centre it rises, with artificial additions, to a height of 400 ft.

In a circle round the crest of the hill is the ditch of the Norman castle, enclosing an area of a little over an acre. In a wider circle, and fitting neatly within the 300 ft. contour line, is another ditch, which once enclosed the outer bailey of the castle and the cathedral church built by St. Osmund and Roger, Bishops of Salisbury.

The outer defence was first made in the early Iron Age, and its British name was Sorvioduni or Sorbiodoni. With the advent of the Saxons its name underwent a change, and the ending — dunum was replaced by burg or burh, each meaning a defensive place. The name appears as Searobyrg in the Anglo-Saxon Chronicle, and is Sarisberie in Domesday Book.

Source: https://www.british-history.ac.uk/vch/wilts/vol6/pp51-53