Llangorse

Llyn Syfaddan is the largest natural lake in south Wales and by some distance the most historically important body of water in Powys.

The village sits at its eastern end: a church, a scatter of houses, and a great deal of traffic in summer heading for the water.

The island

A few hundred metres off the northern shore is a low tree-covered mound. It is artificial, it was built in the 890s, and it was the residence of a king of Brycheiniog.

Tree-ring dating of the submerged oak palisade planks puts the felling between AD 889 and 893. In 916 a Mercian army under Æthelflæd burned it and carried off the king's wife and thirty-three other people, which the Anglo-Saxon Chronicle records under the name Brecenanmere.

It is the only crannog in Wales and it is dealt with fully on its own page.

The lake itself

Shallow, eutrophic and about a mile and a half long, formed in a hollow left by glacial ice. It is a Site of Special Scientific Interest and a Special Area of Conservation, and its water quality has been a live and rather contentious issue for decades because of agricultural runoff in the catchment.

It holds pike, perch and roach, and historically held a notable population of the gwyniad-type whitefish, though the identification and current status of that are matters for fisheries biologists rather than for this site.

The stories

Giraldus Cambrensis passed this way in 1188 and recorded that the lake sometimes turned green or red, that it was covered in buildings and gardens, and that its birds would sing at the command of the rightful prince of Wales.

There is also the drowned city: a settlement beneath the water, taken for its wickedness, with towers visible on a still day and bells audible.

It is tempting to read that as a memory of the crannog's destruction in 916.

The church

St Paulinus, medieval with Victorian restoration, in a churchyard at the centre of the village.

Now

The lake is used for sailing, rowing, paddleboarding and open-water swimming, with a common on the shore, a campsite and a boat hire operation. It gets extremely busy on a hot weekend and the roads around it are not built for it.

There is a low-level path round part of the shore and a good view over the whole thing from the slopes of Mynydd Llangorse to the south-east, which is the best way to understand why anybody would build an island here.