[1] In 1251, Ottokar's father King Wenceslaus I of Bohemia had not only granted him the title of a Margrave of Moravia, but also installed him as duke of Austria and Styria, territories that were princeless after the ruling Babenberg dynasty had become extinct in 1246.

The quarrels were at first settled with the aid of Pope Innocent IV in 1254, when Béla received large parts of Styria and later installed his son Stephen as a duke.

As none of the belligerents dared to cross the river, Ottokar proposed an agreement, that his troops would withdraw to give the Hungarians the opportunity to go reach the other bank.

As they pulled back, Béla's son Stephen started an attack, went over the Morava and reached the retiring Bohemian cavalry at the village of Kressenbrunn.

The fight is considered one of the biggest battles in Central Europe in the Middle Ages, though scholars doubt the possibility of supplying such a vast number of mercenaries.