 Golubac Fortress has had a tumultuous history . Prior to its construction it was the site of a Roman settlement . During the Middle Ages , it became the object of many battles , especially between the Ottoman Empire and the Kingdom of Hungary . It changed hands repeatedly , passing between Turks , Bulgarians , Hungarians , Serbs , and Austrians , until 1867 , when it was turned over to the Serbian Knez , Mihailo Obrenović III . Now , it is a popular tourist attraction in the region and a sightseeing point on Danube boat tours . 
