In Irish legend, Clothru was a daughter of Eochu Feidlech, then High King of Ireland.

One point is called Grianan Meva ("Medb's sunny place"), and nearby is Innadmarfa Meva (Ionad Marbhtha Meidhbhe, "Place of Medb's death"), where she was killed by a stone thrown from Elfeet Castle, on the Longford side of the lake.

In other versions of the legend, it is a lump of cheese fired from a slingshot by a nephew of Clothru.

Between 800 and 1300 the island and its churches were repeatedly plundered and burned by invaders, so the buildings are in ruins today.

Teampall Diarmada is the monastery founded by Saint Diarmaid the Just (who was a teacher of Ciarán of Clonmacnoise) in 540 AD.

The walls have lost their distinctive features of detail, except for the east window, which is similar in construction to that of the Teampall Clogas.

Near this church, half buried with its face downward is a stone bearing incised on its surface a Celtic interlaced cross with an Irish inscription.

[8] It has a square bell tower (Irish: clogas), which is attached to the main building.