Castle an Dinas: the St Columb hillfort where a duke died

Fly a drone over the fields near St Columb Major and you find it before you understand it. Three great rings, cut into the hillside two thousand years ago, sitting one inside the other like ripples that never faded. From the ground it is a climb and a view. From above, it finally looks like what it always was, one of the largest hillforts in Cornwall.

A gathering place, not a fortress

Castle an Dinas sits on the summit of Castle Downs, 700 feet above sea level, with views reaching to both the north and south coasts on a clear day. It was built between the fourth and first centuries BCE, and consists of three concentric ditch and rampart rings spanning 850 feet across.

Archaeologists no longer think of hillforts like this one as military strongholds first and foremost. They are now understood as something closer to a community’s beating heart, a place of focus for the tribe, used for social ceremony, trade and ritual rather than simply defence. Excavations in the 1960s found that the main period of use was the Iron Age, when the ramparts would have stood at their tallest, likely topped with a wooden palisade, with a cobbled entrance on the south-west side.

There are traces of even earlier activity too. Two Bronze Age barrows sit within the enclosed area, and surveys have picked out a levelled platform between the banks that may point to Neolithic use of the hill, long before the ramparts were dug.

The duke who died on the hill

Castle an Dinas earned a second life in Cornish legend, long after the last Iron Age gathering had faded from memory. It is named as one of the seats of the early Dukes of Cornwall, and as the place where Cador, Duke of Cornwall and husband of King Arthur’s mother, met his death. Cornwall Heritage Trust, the charity that now looks after the site, points to the survival of that story as evidence the hillfort stayed significant for centuries after it was built.

Mining, farming and a hidden shaft

The centuries since have left their own marks on the earthworks. A 20th-century wolfram mine cut platforms into the prehistoric ramparts to carry an aerial ropeway, known as a blondin, ferrying ore from workings on the north side of the hill to processing works on the south. Inside the enclosure, a boggy patch nicknamed the “dew pond” may even conceal a mining shaft sunk within the last hundred years, on top of a spot that could originally have held an Iron Age well.

Sheep still graze the site today between April and October under a Higher Level Stewardship agreement with Natural England, keeping the grass and bracken down across land that has now been farmed, mined and celebrated on for two thousand years running.

Visiting St Columb today

Cornwall Heritage Trust took on Castle an Dinas in 1989 from the Duchy of Cornwall Estate, and it remains one of the largest sites in the charity’s care. Well behaved dogs are welcome, though owners are asked to keep them on leads when sheep are grazing and to clean up after them. iWalk Cornwall has a dedicated walk guide around the hillfort for anyone planning the route.

📷Credit: Cornwall Heritage Trust

Full directions and access details for Castle an Dinas, and the Trust’s other sites, are on the Cornwall Heritage Trust website. The address is St Columb Major, TR9 6JB, on OS Map 200 at grid reference SW 945624, and dew pond aside, nobody has yet confirmed what, if anything, is actually down that shaft.