From the late 12th century onwards, the fortresses of Wiener Neustadt and Hainburg were erected at the southeastern and eastern rim as a defensive wall against attacks from the Hungarian lands downstream the Danube River. Nevertheless, the forces of King Matthias Corvinus entered the Vienna Basin during the Austrian-Hungarian War in 1485 to begin the Siege of Vienna. It was again invaded by Ottoman troops, who besieged the city in 1529 and 1683.