Llangorse Crannog

A crannog is an artificial island built in a lake to live on. Ireland has hundreds and Scotland has plenty. Wales has one, and it is in the largest natural lake in south Wales, a few hundred metres off the northern shore.

Finding it

It was identified in 1867 and dug in 1869 by two local antiquaries, Edgar and Henry Dumbleton, who published what they found. Then it was more or less ignored for over a century, partly because the received wisdom held that Wales did not have crannogs.

In 1988 tree-ring dating of the submerged oak palisade planks put the felling of the timbers between AD 889 and 893. That is an extraordinarily tight date for anything in early medieval Wales. A joint Cardiff University and National Museum Wales excavation followed from 1989 to 1994, with further work in 2004.

What is there

An island of brushwood and sandstone boulders, ringed by several lines of oak plank palisade, built by people who understood the technique and had almost certainly learned it in Ireland — which fits the Brycheiniog dynasty's own claimed Irish descent.

The finds are what mark it out as royal rather than merely defended. Over 40,000 fragments of animal bone, indicating feasting on a considerable scale. Fine metalwork, both secular and ecclesiastical. And, preserved in waterlogged mud, an embroidered textile of a quality that has no parallel anywhere in Wales from this period, decorated with birds and vine scroll in silk and linen.

Why it was built

Viking raiders reached Brycheiniog in 896 and the kingdom's rulers had already sought the protection of Alfred of Wessex. An island reached by a single causeway is a great deal safer than a hall on open ground.

The Llandaff charters name kings of Brycheiniog and describe an estate of some 400 hectares around the lake. The crannog is generally accepted as the residence of Tewdwr ab Elise, king of Brycheiniog around the turn of the tenth century.

The end of it

In 916 a Mercian army under Æthelflæd, daughter of Alfred and ruler of Mercia, came to a place the Anglo-Saxon Chronicle calls Brecenanmere, burned it, and took away the king's wife and thirty-three other people.

That entry is one of very few securely dated events in early medieval Powys, and it was recorded by the people who did it.

The legend, and why it is not the same thing

There is a long-standing story that a city lies beneath the lake, drowned for its wickedness, with towers visible on a still day. Giraldus Cambrensis heard something like it in 1188.

It is tempting to read the legend as folk memory of the crannog's destruction.

Visiting

There is no access to the island, which is a scheduled monument and fragile. It is visible from the shore at Llangorse as a low tree-covered mound, and from the lakeside path on the western side.

A full-size reconstruction stands at the National History Museum at St Fagans. The finds, including the textile, are held by Amgueddfa Cymru in Cardiff.