At the southernmost tip of the Western Isles, south of Barra, lie the small islands of Pabbay, Mingulay and Berneray. The term 'Bishop's Isles' refers to the fact that the island south of Barra were in the possession of the Bishops of Man (the Isle of Man) and Sodor, this being a legacy from the era of Norse occupation which lasted until 1266, when all the Hebridean islands were ceded to the Scottish Crown by King Haakon of Norway under the Treaty of Perth.

The islands can lay claim to a religious and historical association stretching back well over 1000 years. But in fact they contain evidence of human occupation by prehistoric peoples possibly from the late Bronze Age and well into the Iron Age, which ended about 400AD.

Because they are now uninhabited, the islands have been declared sites of special interest and protected areas, on account of the fact that they are important for species of breeding seabirds. Their relative inaccessibility ensures that the birds are not disturbed while bringing up their young.