Sir Richard Colt Hoare writes in Chapter 10 of The Ancient History of Wiltshire (1812):
Amongst the ancient cities of our realm, there are few whose vicissitudes of fortune have been more various, or whose history has been more perspicuously recorded, than that of OLD SARUM. The dry and elevated hill on which it formerly stood, was successively occupied by Britons, Romans, Saxons, and English, and during the empire of the Romans in Britain, was distinguished by the Latin appellation of SORBIODUNUM, and the succeeding area of the Saxons by that of SEARBYRIG, SEAROBYRIG, SEAREBERI and SAARESBYRI, which in more modern times has been changed into SALISBURY.
[...]
The name of SORBIODUNUM, and the numerous raised causeways issuing from it in various directions (of which I shall hereafter give a minute detail) most clearly attest the occupation of the Romans, though in the bold ramparts still remaining of the old city, we cannot trace any vestiges of that form of castrametation which was usually adopted by them. This strong post was probably wrested from the Britons during the reign of the Emperor Claudius, when his general, Vespasian, is said to have taken twenty British towns, and to have subdued two powerful nations, one of which is supposed to have been the Belgae, who inhabited the western counties of Hampshire, Wiltshire, and Somersetshire.
[...]
But however fallen are the walls of this once celebrated city, the remains of its proud ramparts, and its exalted situation, still continue to attract the attention of the antiquary, the stranger, and the neighbouring inhabitants. On comparing the plan of OLD SARUM, with the camps already engraved, you will at first sight perceive that the depth of its ramparts is far greater than any I have yet described; they exceed one hundred feet, whilst those of the fine camps at Yarnbury and Amesbury scarcely exceed fifty. The form of this work inclines to the circle; the area contains 27 acres and a half, and the circumference of the outward ditch is 7 furlongs 26 yards. Within the area is a circular earthen work, rising to a greater height than the outward one, and probably was the citadel: the valla of the outward and inner work are nearly of an equal height, those of the former being 106 feet, and those of the latter 100 feet. The area between the outward and inner work is in three places subdivided by earthen banks; a few fragments of ancient walls remain, and the spot is pointed out where the old church was supposed to have stood, near the western portal. There were two entrances to this city: the principal one, guarded by a horn-work, towards the east, and a smaller one, towards the west.
Link to a plan of Old Sarum and illustration of the landscape at Old Sarum from the same book.
Something is not right. This message is just to keep things from messing up down the road