It was the original Catholic bishopric in Norway (Latin: Selia; now a titular see) which later became the pre-Reformation Ancient Diocese of Bergen (Bjørgvin).

The island is located in the Sildagapet bay, just 1 kilometre (0.62 mi) west of the harbor in the village of Selje.

The painter Bernt Tunold grew up on the island, where his parents had established a farm on the church grounds.

The discovery at Selo in 996 of the supposed remains of Sunniva and her companions led Norwegian King Olaf Tryggvason (995-1000) to build a church there.

Today, the ruins of a monastery named "Sankta Sunniva kloster" (Selje Abbey) is the only notable feature on the island.