St. Hans and St. Peter churches were built side by side during the 1200s. St. Peter was consecrated to the apostle Peter. St. Hans, which was the larger church, was dedicated to St. John the Evangelist. It was where the Lutheran doctrine for the first time preached on the island. In 1527, however, Bishop Brask turned Lutherans out from the church. But as soon as the bishop sailed to Denmark, Lutherans worships were started again. Churches were demolished in 1600-1800s and the stone was used among others to construct Lythbergska house. In 1982 a beautifully decorated gravestone was found in the ruins of in St. Hans, dating from 1050s.
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.