Béla had had his eldest son, Stephen crowned junior king already in 1246, but he did not want to share the royal power with his son.

However, Stephen recruits an army against his father and in 1258 persuades Béla to cede him the government of Transylvania, which had been among the territories devastated by the Golden Horde during the Mongol invasion of Europe in 1241-1242, during which a large portion of the population had perished.

In the same year, the Styrians, who would have preferred the rule of the King of Bohemia, rise against Béla's reign, but his troops suppress their rebellion.

After his victory, Béla appoints his son Duke of Styria.