It's taken surprisingly long, but a neolithic tomb in Herefordshire, England, is being studied by archaeologists. The site has an extra pertinence having been incorporated into the Arthurian legend, but the size of the chamber being revealed suggests it would have plenty of interest without that subsequent layering.

Even in a land dotted with ancient stone constructions, Arthur's Stone stands out. Erosion has revealed the once-buried chamber is made up of nine upright stones and a capstone thought to weigh at least 25 tonnes. As with other neolithic monuments, such as Stonehenge, transporting the capstone and moving into place would be an engineering feat today, let alone thousands of years ago.

The capstone has been claimed as the inspiration for the stone table on which Aslan is sacrificed in The Lion The Witch and The Wardrobe. Surprisingly, no one has tried exploring what is inside, or at least been recorded doing so. Archaeologists from the Universities of Manchester and Cardiff are finally rectifying this.

Preliminary investigations last year by Professors Julian Thomas and Keith Ray revealed the visible stone architecture does not stand within a wedge-shaped cairn, as previously suspected. Instead, the monument once extended to the southwest, and may originally have been a turf mount with rounded ends, with additional stone chambers added to it later. 

“Although Arthur’s Stone is an iconic Megalithic monument of international importance, its origins had been unclear until now. Being able to shine a light on this astonishing 5,700 year old tomb is exciting, and helps to tell the story of our origins," Thomas said in a statement at the time.

Three similar mounds have been found on nearby Dorstone Hill, to which the first stage of the chamber points. The archaeologists are starting to see the entire upland area, located near the border of England and Wales, as hosting an integrated set of Neolithic monuments.

The Dorstone Hill mounds have been found to contain multiple bodies, along with flint tools, arrowheads, and pottery. “Each of these three turf mounds had been built on the footprint of a large timber building that had been deliberately burnt down,” Thomas said.

The team stressed they are only exploring the periphery of the mound to learn its scale, and are not, in Thomas's words, “trying to mess around with any human remains that may have been deposited here at any point.”

"Arthur's Stone is one of the country's most significant Stone Age monuments, and this excavation gives a really rare and exciting chance for members of the public to come and see archaeology in action," said English Heritage's volunteer manager Ginny Slade in a statement. English Heritage have organized a team of volunteers who will explain the dig to tour groups who book through their site.

The story of a king who brought peace and temporary good rule to Britain has proven so captivating, particularly in times of chaos and danger, that dozens of sites such as the tomb have become associated with him in local lore. The practice even extends to former British colonies. The contradictory tellings of the tale of the virtuous king are so diverse, that almost any monument can find a place in some of them.

As with almost everything else about the Arthurian legend, there are many different versions of how the stone is connected to Arthur, including a battle fought at the site and stones bearing the mark of either a falling giant foe or Arthur's own knees.

None of this would have meant anything to those who built the tomb. The earliest surviving references to Arthur protecting Wales and western England from invasion and supernatural forces are more than 3,000 years younger than the most recent possible building of the monument.