Lambay Island is the largest of the Fingal Dublin Coast islands. Located opposite Portrane it has had a chequered history, St Colmcille built a monastery there, it was occupied by the Vikings, owned by the church, and a prison camp. There are two monuments located on the island a late transitional castle and a large adjacent rectangular earthwork. The Baring family, the famous British Banking family, bought the island in 1904. The island is an internationally important seabird colony and one of the top seabird sites in Ireland. In addition to the seabirds, it supports a nationally important population of Greylag Goose and is also an area of conservation for the population of Grey Seal. Lambay has essentially been maintained as a wildlife sanctuary by its owners since the early 20th century and the policy of preservation of wildlife continues.