St Elidyr's Church was the principal place of worship of the Cawdor family, former owners of the Stackpole Estate. The church has medieval origins, but most of the original structure, apart from the 12th or 13th century tower and part of the chancel, has been absorbed into later additions and renovations.
The church is built on a slope in a wooded valley, the slope partly excavated to accommodate the building. Cruciform in plan, the chancel is about 6.5 metres long by 4.5 metres wide. There are north and south transepts, a vestry and a chapel. There is an open porch to the south, within which there is an early medieval inscribed stone. There was a crypt beneath the chancel, now filled in. The roof is slate, and there is a wrought iron cross at its eastern end. The altar table is oak, as are the communion rails.
The tower is a prominent feature and an older part of the church. It is of a typical local design with a parapet, but unusually slender. The lowest storey has a vault opening into the north transept. Two upper floors and the roof are crudely constructed. Each storey has windows or louvred openings, the lowest being blocked. The top storey has louvred openings on all four sides and there is a spiral staircase.
A stone cross with a modern head stands in the churchyard.
References:Towering 52 meters above the sea, Bengtskär lighthouse is the tallest one in Scandinavia. The building started in in 1905 after the shipwreck of S/S Helsingfors and was completed in 1906. The lighthouse was designed by architect Florentin Granholm. On December a special petrol lantern, designed and built in Paris, was brought to Bengtskär and installed atop the tower.
German fleet bombarded Bengstkär in the First World War in 1914. Since the Gulf of Finland was heavily mined, it was not until 1919 that the surrounding seas were declared safe for shipping, that the light was lit again.
After the war the military value of Bengtskär increased as part of the defence system of independent Finland. In Second World War (1941) Soviet Union made a suprise attack to island. After a bloody battle, the small Finnish garrison emerged victorious. Intermittent repairs to the facility continued during the post-war period.