During the 12th century, there appears to have been a tower and wooden fort at the site of the present Erpeldange castle. In the 13th century, Frederic and Gerard d'Erpeldange, the first lords of Erpeldange, built a fortified stone castle guarding the valley at the point where the River Sûre meets the Alzette. The property passed successively into to the hands of the Counts of Vianden, and the Brandenburg-Outscheid and von Moestroff-Kerpen families.
Through marriage, the Gondersdorf family inherited the castle and in 1630 transformed it into a luxurious residence for their daughter. In 1677, it was inherited by Charles François baron de Failly de Sancy and Marie Marguerite de Giraldin. By that time, it was no longer of any military value as a quiet park had replaced its defences. Abandoned by the Prel family in the 19th century, it was used as a rectory. During the Second World War, the castle was damaged as a result of its use first by the Germans and then by American troops.
The castle changed hands a number of times until it was acquired by the State in 1983. The commune's administrative offices have been housed there since 1987. The building still contains two fine Renaissance fireplaces.
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.