Around the turn to the 2nd millennium, the Hungarian frontier ("Gyepű") ran along the Leitha shore, from 1156 onwards it formed the eastern border of the Duchy of Austria with fortresses erected at Wiener Neustadt, Bruck and Hainburg. The last Babenberg duke Frederick II of Austria was killed in the 1246 Battle of the Leitha River against King Béla IV of Hungary. The course of the border was confirmed in a 1411 deed issued by King Sigismund, when his daughter Elizabeth married the Habsburg duke Albert II of Austria.