In September 2022, Cornwall National Landscape’s ‘A Monumental Improvement’ project (MI), with funding from The National Lottery Heritage Fund, commissioned the Cornwall Archaeological Unit (CAU) to carry out archaeological investigations to the site to define a clear chronology of the monument, understanding its use and relationship in the wider context of the landscape as well as understanding the longer-term conservation needs of the monument. The site is included on Historic England’s Heritage at Risk Register due to unchecked vegetation growth obscuring the monument.

The site, which is a scheduled monument, is a solitary structure in a remote area of common grazed land on Bodmin Moor. It consists of a rectangular bank of earth and stone, measuring 21 x 49 metres internally, formed with 56 orthostats (standing stones) surviving on the inner face of the embankment, some measuring up to 1.8m, which are either leaning, recumbent or partially buried.

The Historic England listing for the site denotes it as a Medieval animal pound but the new dating results confirm that the monument is actually 4,000 years older than previously thought. There has long been speculation that the monument could be a prehistoric structure, due to the standing stones, its north-south orientation and its position in a part of Bodmin Moor with many other early sites and now we have the dating evidence to confirm this.

Phil McMahon, Inspector of Ancient Monuments at Historic England, said: “We have supported the investigations at King Arthurs Hall with grant funding and specialist advice to ensure that the cutting-edge scientific methods used to analyse the monument had the best chance of producing results.

Because King Arthur’s Hall is on our Heritage at Risk Register, our overall aim was to better understand the date and nature of the monument so that its condition could be improved and its future management tailored to its needs. The news that King Arthur’s Hall is Neolithic in origin is exciting and adds significant time depth to this enigmatic site, which has few parallels in England. It enriches the story of the monument and adds an intriguing dimension to the wider prehistory of Bodmin Moor.”

The excavation was undertaken with help from trained local volunteers and the dating for the excavation was carried out by specialist teams from the Universities of Reading, St Andrews and Newcastle using multiple dating methods. Optically Stimulated Luminescence (OSL) dating was used to test and examine material from a section dug through the bank and into soils buried beneath it to determine when the structure was built. Dating from the OSL analysis indicates the structure was constructed in the later fourth millennium BC (Neolithic Period).

Dr Tim Kinnaird, University of St Andrews adds “it’s extremely exciting that we’ve finally been able to date construction of this enigmatic monument, previously grounded in myths and legends. To have a definite date for King Arthurs Hall in the later fourth millennium BC is a major revelation – we now have to re-appraise our understanding of the prehistoric landscape of Bodmin Moor.”

In addition, samples were taken from the interior of the monument to establish the presence of fossil plant and animal remains such as pollen, seeds, insects, and parasite eggs within the sediment. These core samples were radiocarbon dated and revealed that the infilling of the monument began in the Later Prehistoric (2,000 – 2,500 years ago) and medieval dates (500 – 1000 years ago) for monument activities that affected the marshy interior of the enclosure. These activities, which might have included use as a pound and then as a reservoir used in tin streamworking, were probably quite different from those intended by the enclosure’s first builders thousands of years before.

Dr Rob Batchelor, Director of Quest, an archaeological science focused unit at the University of Reading, said: "The wild, remote landscape of Bodmin Moor has inspired centuries of legends, but this extraordinary new finding shows how science can help deliver stories that are just as intriguing. Our part of this work analysing sediment cores, has helped us to understand the shape of the interior of the monument. And our analysis of past plant and animal remains also offer clues about the former local landscape and past human activities that might have taken place there. Further analysis of these sediment cores may yet reveal more about what our Cornish ancestors were doing there and their impact on the local environment."

Geological examination of the standing stones suggests that they came from within 250m of the site and were possibly dug out from the interior rather than from a distant tor.
Although there are rare henge monument forms elsewhere where banks are lined with stones (e.g., Grange Circle, Lough Gur, Ireland or Meini Gwyr, Wales), these sites are circular which makes the monument highly unusual, if not unique. Rectangular monuments do exist in Brittany (e.g., Crucuno), but without the enclosing banks. Possible uses in the later fourth and third millennia BC may have included gatherings of local communities for ceremonies and rituals, but as the site is so unusual, its original purpose remains uncertain.

James Gossip, Senior Archaeologist from Cornwall Archaeological Unit (CAU) and fieldwork director for the project, said “the King Arthur’s Hall project provided a once in a lifetime opportunity, using scientific dating to understand more about this unique and enigmatic monument - the main question being, when was King Arthur’s Hall built?
The job of the archaeologists was to find deposits relating to the building of the monument. A team of dedicated volunteers spent a week helping CAU archaeologists dig and record a trench which cut through the bank of the monument, successfully revealing an ancient land surface which had been buried beneath the monument for 5000 years.
Once we had identified these sediments buried below and within the bank of the monument, specialists from St Andrews and Newcastle Universities could take samples for dating.

Knowing when King Arthur’s Hall was built will help us understand this unique monument form better, how it might have originally been used and how it could have been used over time. It gives us a framework for further questions – for instance were the stones placed there at the time of building or later in prehistory, how was it used as part of the surrounding landscape, and can we find evidence for later uses such as an animal pound or reservoir?”

Pete Herring, President of the Cornwall Archaeological Society observes that “The romantic sounding 16th century name King Arthur’s Hall tells us that here is a place regarded by the moorland community as something ancient and unfathomable, like other sites attributed to Arthur. Science has responded to that name’s challenge, providing a very early date of origin, and two other dates, later prehistoric and medieval, when there was activity at the enclosure.

The monument retains its mystery: there are no Neolithic parallels for a stone-lined sunken and embanked rectangular enclosure, possibly watery. We may presume it was a sacred site, a place for gatherings, for rituals or ceremonies, but perhaps Neolithic people made and used it for very different purposes. Its later prehistoric and medieval dates for reuse may relate to two of Cornwall’s great sources of wealth, supporting the sustainable summer grazing of extensive commons, and then serving as a reservoir for water used in tin streamworking.

These dates, remarkable as they are, encourage further research into King Arthur’s Hall.”
Confirmation of the monument’s original construction within the Neolithic period will help the Monumental Improvement project team, Historic England and many others to better understand the site. As a unique and ancient site, it needs very special care and attention to preserve its significance for future generations to enjoy.

A management plan for the site is being developed in partnership with Historic England, Natural England, the landowner and the Hamatethy Commoners, the first step of which has been to replace the fence surrounding the monument which had fallen into disrepair, to prevent erosion from cattle.

Cornwall National Landscape’s Monumental Improvement project will also be creating interpretation for the site to help visitors better understand its significance. This will include digital interpretation on the Cornwall National Landscape’s website so that more people can access and explore this unique piece of history.

This excavation and the scientific analyses were made possible thanks to funding from The National Lottery Heritage Fund through the Cornwall National Landscape’s ‘A Monumental Improvement’ project, Historic England, Cornwall Council and Cornwall Heritage Trust. With thanks and support from the landowner and Hamatethy Common, Natural England, Cornwall Archaeological Unit, specialist teams from the Universities of Reading, St Andrews and Newcastle as well as amazing local volunteers.

This protected scheduled monument is at risk from erosion caused by visitors and sits within Section 12 (Bodmin Moor) of Cornwall National Landscape. Livestock is grazed on this area of the Moor and visitors must take care to follow the Countryside Code and not to disturb the monument or livestock in any way.