Excavations in the 1970s confirmed that the pre-Roman Iron Age hillfort Cadbury was reoccupied in the late 400s, Leslie Alcock suggested a date of the 470s, with its defences reconstructed with a new dry stone wall atop its upper earthen rampart.
This is quite unusual given several factors.
No other site of the era has been found that is on the scale of Cadbury - all others are essentially a walled farmstead just large enough for a single extended family which could fit on Cadburys summit several times over, in other instances of Iron Age-era hillforts being reoccupied only a small area of the summit was refortified. The next largest is the interestingly nearby Cadbury-Congresbury which is half the size of Cadbury and its reconstruction featured a wall bisecting its summit walling only half of it in.
I am grossly summarizing and simplifying this point so please tell me if I am wrong but in short as I understand it the economy, trade, and manufacturing all seem to have broken down by this point after the Roman withdrawal. No coins appear to have been being minted or in circulation, older coins were being turned into jewelry or placed in graves; trade with the continent seems to have become very infrequent and light with only Monastic and wealthy coastal locations showing any examples (yet another notable feature of Cadbury is it is one of the few locations that is both non-Monastic and inland with any sign of such imports); and for a manufacturing example things like turned pottery ceased to be locally produced with simpler thrown pottery reappearing.
And as impressive as its defences must have been as I said it was topped with dry stone rather than mortared - I don't recall Alcock making the connection in his description of the wall but it looks like they somehow recreated on a small scale the murus gallicus technique - a step backwards for people who would have been living among the remains of Roman masonry.
So with all that now out of the way... who did this, how can there be no record of something like this?
And why was it on this enormous scale, what prompted something so much more massive than anything else of its era?
And how did they manage to accomplish this, where and how did they get the resources and manpower in the deprived conditions they appear to have been in for something of this magnitude?
It is such an unusual site given its scale for the era yet there doesn't seem to be much interest in returning to it since Alcocks initial work, everything seems to just cite that with nothing since. In contrast to this locations like Tintagel continue to be studied. Is there a reason for this lack of interest, is it considered too damaged by later occupation and farming?
Why is there no (written) record?
There are very, very few textual sources for this period in Britain. Although we can get a general sense of cultural shifts, trying to pin down the identity of specific groups or people and why they did things is pretty tricky. I’ve talked about the paucity of written evidence for sub-roman/early medieval Britain on this sub before, and the chances of having one specific community discussed in them are unfortunately very slim. The reasons for the paucity of evidence are:
Writing may not have taken off to the same extent as it did in other parts of the Empire. Britain has a relative lack of monumental inscriptions, especially from people with non-Romanised names, which suggests that maybe people weren’t into it.
Britain has a very, very wet climate that does not generally lead to the preservation of any documents that haven’t been carefully kept. Unlike somewhere like Egypt, you can’t expect a cache of letters to find their way into wrappings or be preserved in a cave. Some documents have survived - the Bloomsbury and Vindolanda tablets for example - but they’re unfortunately much earlier then the time period you’re interested in.
Most of the writing that survives was done by Christian officials and hagiographers. They’re concerned with very big events and with some places where specific big events occurred, like St Germanus’ visit to St Albans. Much of the time they are not writing histories or for posterity, but for their own time and place, and use terms and make references we cannot fully understand. The first record we would expect to see for a site like this - assuming that it wasn’t mentioned in a surviving chronicle or charter under a name we don’t recognise - would be in the Domesday Book, by which point the site had been abandoned as an ongoing concern. I am, of course, discounting all of the discourse around Cadbury and Camelot, mostly because it is built entirely and irritatingly on sand.
Is dry stone walling backwards?
I’m being a little facetious here, but just to avoid the myth of history working like a tech tree: what’s happening at Cadbury isn’t “backwards” from where people were a century earlier. Dry stone walling, for example, is a highly skilled task and one that was clearly suited to their environment and needs. Early medieval people abandoned technologies that weren’t working for them and kept ones that did.
Whether they were ‘deprived’ is a good line of inquiry. Although the monetary economy had likely dropped out and there is a relative paucity of trade goods from outside the country - although they are still flowing into elite centres - was this a negative impact for most people? There are skeletal indications in early medieval cemeteries for an overall improvement in stature and nutrition as well as a decrease in dental disease from the Roman period. The Roman period itself is a nosedive in terms of health from the Iron Age. Based on this, there may have been a generally improved life experience, even if many people were only able to access goods from within a smaller radius.
Clearly there was both a sufficient and sufficiently motivated population at Cadbury to undertake the project of refortification and somebody present in c. 470 who was capable of generating enough support to direct such a project. Comparisons could be made to neolithic monuments or to the building of hill forts to begin with; people in large groups are capable of some very surprising feats of construction and earth moving.
Why is it so large?
This is a good question. The defended area is maybe double the size of any other known early medieval fort, with a 4-5 metre rampart that spanned maybe 1200 metres and had a wide wooden walkway at the top. It would have been extremely expensive in terms of manpower to build and maintain, which may have contributed to its abandonment well before similar forts.
They clearly had a purpose for refortifying the site, whether that’s a fear of violence, an elite display of power or ambiguous religious reasons. Another theory is that system collapse may have lead to a conscious decision to reinvest in a “celtic” identity, manifesting itself in the refortification of sites like Cadbury - a conscious desire by new dynastic kings to link back to a pre-Roman past. It may indicate that whoever was in charge commanded a significant amount of power.
One other theory is that it was re-fortified to provide a secure administrative centre to replace the nearby town of Lindinis (modern Ilchester), which would also have provided access to craftsmen like blacksmiths and a good market site to the surrounding countryside. We know that Lindinis experienced flooding after the fourth century, which may have prompted a settlement shift. There has been some speculation over what the general height of the Somerset Levels was at the time and whether Cadbury was in fact close to navigable waterways which would have provided access to the Severn and allowed it to control nearby trade, including in slaves and tin.
Why hasn’t there been a large scale excavation since Alcock’s?
Archaeological excavation is expensive and time consuming. A lot of modern archaeology is either rescue archaeology - where for e.g. a site is literally falling off of a cliff due to erosion, and if you don’t excavate now no one ever will - or happening ahead of construction, where archaeologists are called in because someone has found a bit of a structure or skeletal remains. There’s also a great adage that if you don’t have to excavate something, you shouldn’t. Someone will always be along in twenty or thirty years with better and less invasive techniques. As Cadbury Castle is a relatively stable site and legally protected so that no one can build a new estate over the top of it, it’s fine to leave it alone until someone can make a convincing argument for digging new trenches (1).
That said, the South Cadbury Environs project has been working on and around the site since the early nineties, mostly using non-invasive techniques like GIS. This is due to a wider interest in landscape archaeology in late 20th and 21st centuries. They’re interested in linking it with wider cultural identities and land use, rather than examining the site in isolation, and I think some interesting stuff has been coming out of it.
(1) I believe it has been taken off of the Heritage at Risk register as of 2020, which it was previously on due to the impact of erosion. A victory for good heritage management!