Well, this was a turn up for the books this sunny, winter afternoon... a major hillfort instead of the denuded remnants of earthen banks I was expecting to supplement the trashed, yet still evocative Pitchbury Ramparts this morning. To be fair, the 'Iron Age' origin of Erbury has yet to be conclusively determined, in no small part due to the incredibly rich history of occupation at the site. Hey, tell me about it.... notably the home of Aelfric, a prominent Saxon thane and son of Withgar (according to the Wikki... oh, and some 'Domesday Book', or other), no doubt the enclosure was also utilised in some respect by the powerful Norman interloper de Clare, whose motte and bailey castle once controlled the River Stour south of the church (surprise, surprise)... and who 'generously' gave his name to the town. Later, the site was incorporated within the medieval common, still extant, the majority of interior detail apparently dating from this time. In short, quite a challenge for archaeologists seeking answers, methinks? However.....
A field survey/magnometric scan conducted during 1993 determined that 'the stratigraphy of the earthworks confirms the likelihood of a prehistoric origin.' [Clare Camp: An Archaeological Survey by the Royal Commission on the Historical Monuments of England, September to October 1993, Archive Report, p15]
More recently, construction work at Clare Primary School in 2009 discovered postholes/a ring ditch of a late Bronze/Early Iron Age structure nearby [Suffolk Institute of Archaeology & History, Vol XLII Part 2].
It also has to be said that it looks very much like an Iron Age defensive enclosure, too. Particularly if, having seen many examples upon his travels, this punter is not put out by a less than perfect strategic placement... to my mind defence was but one consideration to be taken into account by the Iron Age planners - albeit a very important one - the metaphysical requirements seemingly just as important. No doubt the priests' voices were heard loud and clear, the proximity of the Stour and its tributaries perhaps rendering their views decisive?
The enclosure would appear to be (at least at the best preserved northern and southern flanks) powerfully bi-vallate, the eastern and northern banks now encroached upon by the houses of the town which outgrew their protection. Only to the west are the defences badly eroded, to the point of partial destruction. The common is alive with locals today, some walking dogs, some.... just walking. A black cat deems it necessary to sit upon the outer bank and keep a close eye upon me, 'yoofs' on bikes deciding the man taking pictures of 'nothing but the sky' is not worth challenging. Yeah, impressive as Erbury's earthworks are, they pale into insignificance beneath the towering magnificence of the winter sky.... then there are the snowdrops sheltering from the sunlight beneath the eastern bank.... awaiting Spring.
This is probably Iron Age - it was originally on a spur of land overlooking impassable marshes. Now it's rather encroached on by housing and the outer bank and ditch are largely destroyed. You can still see the inner bank and ditch. It used to be known as Erbury ('earth fortification') and may have been used by the Danes.