The Brough o' Deerness from the landward side of the original land bridge.

Jutting out into the North Sea, on the north-eastern coast of the Orkney Mainland, is a large grassy rock known as the Brough o' Deerness.

The Brough, on top of which are faint traces of a settlement, surrounding the visible remains of a 10th century chapel, was once connected to the Mainland by a land bridge. This has long since crumbled away.

Now the site is not one of the easiest to reach - the visitor must first negotiate a slippery and muddy descent to the bottom of Little Burrageo, before a steep, narrow ascent along the south face of the Brough to reach the summit.

The collapse of the land bridge must have occurred before the 1500s, as the account of the Brough by Jo Ben, allegedly dating from 1529, describes:

"In the north part of the parish there is, in the sea, a natural rock where the people on hands and knees ascend to the top with great difficulty."

Once on the Brough, the visitor will immediately spot the remains of the chapel, which stand four of five feet high. Dating from the late Norse period, this chapel is the focus of a complex archaeological mosaic, apparently consisting of a bank and wall and a tight cluster of structures.

Some have suggested the bank and wall on the Brough’s landward side are Iron Age defensive ramparts. Others declared them to be a "Vallum Monasterii" - a symbolic barrier for a monastery.

But there remains no proof either way. Along the same lines, very little is actually known about the settlement.

The Brough o' Deerness, as seen from Little Burrageo. The path leading to the summit of the Brough is on the facing rock face.

Early historians had no doubt. They declared the site to be an early, pre-Norse, "ecclesiastic settlement". More recently, however, scholars have firmly placed the rectangular buildings firmly in the Viking era, dating from the 12th and 13th centuries.

However, despite excavations in the 1970s, too little is known about the site to be able to date it exactly, or even know for sure what it was used for.

A complete archaeological excavation is required to settle the arguments over whether the site is an Iron Age promontory fort, early Christian monastic site or a Norse secular site.

The bank and wall on the landward side of the Brough have been suggested by some to be Iron Age defensive ramparts. Others declared them to be a "Vallum Monasterii" - a symbolic barrier for a monastery.

But to date there remains no proof either way.

Early historians had no doubt, however, and declared the site to be an early pre-Norse, "ecclesiastic settlement". More recently, however, scholars have firmly placed the rectangular buildings firmly in the Viking era, dating from the 12th and 13th centuries.

However, despite excavations in the 1970s, too little is known about the site to be able to date it, or even know for sure what it was used for.

A complete archaeological excavation will be required before the arguments over whether the site is an Iron Age promontory fort, early Christian monastic site or a Norse secular site can be settled.