Ancient British fortress uncovered in woodland

A massive long-lost prehistoric fortress has been discovered by archaeologists in northern Yorkshire.

Preliminary examinations of the remains suggest it was among the biggest and most impressive fortresses built by the ancient Britons. Constructed during the Iron Age, about 2,400 years ago, it appears to have extended to a little above 40 acres, more than twice the size of most other prehistoric strongholds.

The fortress, which was uncovered during survey work by archaeologists from English Heritage and North York Moors National Park, consists of a 1.3 mile circuit of ramparts, 60 per cent of which are cut out of solid limestone.

Although the earthworks stand up to 10 feet high, archaeologists had been unaware of the fortress, which is in scrub and woodland, before the survey work. A stretch of the earthwork 670ft long had been noticed by Ordnance Survey cartographers in the 19th century – but had been regarded simply as part of an ancient boundary ditch.

The fortress was constructed on the edge of the North York Moors at Roulston Scar, 20 miles north of York and took spectacular advantage of the moorland topography. Built on a strategically important promontory overlooking the Vale of Mowbray, its ramparts ran for part of their circuit along the top of a cliff about 100ft high.

But the discovery has presented scholars with an archaeological mystery. For although the fortress must have taken several years – and more than 10,000 cubic metres of earth and rock, and 3,000 trees – to build, nobody seems to have lived there for any length of time.

Most Iron Age fortresses, known to archaeologists as hill forts, were more akin to fortified villages or walled towns, often with substantial permanent populations. The evidence so far from Roulston Scar suggest it never was a permanent settlement.

Instead the fortress may have been built purely for military, political or symbolic reasons at a time of strong inter-tribal rivalry.

Significantly, the stronghold faces what was in Iron Age times the territory of the Brigantes tribe, on the border between the Brigantes and their neighbours, the Parisii.

One possibility is that the fortress was built by the Parisian king or paramount chieftain to impress, deter or intimidate their Brigantian neighbours.

Alastair Oswald, the English Heritage archaeologist who led the survey team that made the discovery, said: "Finding a previously unknown Iron Age hillfort is a tremendous surprise. Nothing comparable, of this size or state of preservation, has been found in Britain for many, many years."