On a high point of [this] hill.. is a very interesting monument of antiquity, and by far the most complete of any we have yet met with. I have taken notice of these circles amongst the earthen works in my Introduction.. but the one on Codford Hill so far exceeds all these in symmetry of form, and beauty of situation, that I have purposely reserved my description.. for the present occasion.
This earthen work, is situated on the summit of a hill commanding a most extensive and interesting prospect. It forms nearly a complete circle, the area of which contains above nine acres, and the circuit amounts to three furlongs and one hundred and ten yards. It is surrounded by a neatly formed vallum and foss, which, together with the area, have been much defaced by the plough.
It is vulgarly called OLDBURY CAMP, but the smallness of the enclosure, as well as the slightness of the ramparts, evidently contradict the idea of its either having been made or used for military purposes; it has no signs of any entrance, nor is the ditch within, as we frequently find to be the case in the earthen works appropriated to religious purposes. That this work was dedicated to some juridical or religious ceremonies, the nature of its plan, its size, and elevated situation seem to indicate.
[Colt Hoare goes on to describe how the Persians and others worshipped (on) hills, so tacitly making an analogy with places like Codford]
.. for they say, that the Gods are extremely delighted with such high and pleasant spots. This practice in early time was almost universal, and every mountain was esteemed holy. The people who prosecuted this method of worship, enjoyed a soothing infatuation, which flattered the gloom of superstition.
The eminences to which they retired, were lonely and silent; and seemed to be happily circumstanced for contemplation and prayer. They who frequented them were raised above the lower world, and fancied that they were brought into the vicinity of the powers of the air and of the Deity who resided in the higher regions. But the chief excellence for which they were frequented was, that they were looked upon as the peculiar places where God delivered his oracles.
Codford Circle is a 'hilltop enclosure' on the crest of a hill. It dates from the transition between the Bronze Age and the early Iron Age, and probably had a agricultural function, maybe for granaries. Hilltop enclosures are very unusual, with less than 30 recorded and only in England (though some may have been later been developed into more defensive sites, so disguising their origins). Most are found on the chalk downland of Wessex, Sussex and the Cotswolds, with a few in Oxfordshire and Northamptonshire.
Colt Hoare visited it and recorded that it was known as 'Oldbury Camp' locally. The 1:25000 OS map however has the alternative name 'Wilsbury Ring'.
It encloses eight acres of a flat hilltop, and has views over the Wylye valley.
(from EH's record of scheduled monuments and 'Exploring Ancient Wiltshire' by George Osborn 1982)