Abusina or Abusena was a Roman castra (military outpost), and later of town, of the Roman Province of Raetia.
It was at Eining near Abensberg, on the Upper German- Raetian Limes , which at this point was the Danube River. Abusina stood near to the eastern termination of the high road which ran from the Roman military station Vindonissa on the Aar to the Danube.
In the 2nd century the fort was occupied by the Cohors IV Tungrorum with about 1,000 men. By the later Roman Empire, archaeology and the Notitia Dignitatum suggest the site was occupied by Cohors III Brittonum with only 50 men.
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.