Frederick II

Frederick II, known as "the Quarrelsome", from the dynasty of Babenberg was the duke of Austria and Styria from 1230 to 1246.
He was the second son of Duke Leopold VI and Theodora Angelina, a Byzantine princess. His first wife was Sophia Laskarnia, a Byzantine princess, and his second wife Agnes of Meran.

Frederick fought frequent wars against his neighbors. But most dangerous were his disputes with Emperor Frederick II, who ostracized him in 1236. In 1239, in an spectacular change in imperial politics Frederick II and the Emperor Frederick II formed an alliance.
Duke Frederick II finally died in a battle against the Hungarian king Bela IV at the Leitha river.

As the last Babenberg duke, Frederick "the Quarrelsome" signified the end of an era in the history of Austria.