Béla IV of Hungary
Duke of Slavonia (1220–26)

The senior king ceded the lands between the Adriatic Sea and the Dráva River — Croatia, Dalmatia and Slavonia —to Béla in 1220. A letter of 1222 of Pope Honorius III reveals that "some wicked men" had forced Andrew II to share his realms with his heir. Béla initially styled himself as "King Andrew's son and King" in his charters; from 1222 he used the title " by the Grace of God, King, son of the King of Hungary, and Duke of all Slavonia".

Béla separated from his wife in the first half of 1222 upon his father's demand. However, Pope Honorius refused to declare the marriage illegal. Béla accepted the Pope's decision and took refuge in Austria from his father's anger. He returned, together with his wife, only after the prelates had in the first half of 1223 persuaded his father to forgive him. Having returned to his Duchy of Slavonia, Béla launched a campaign against Domald of Sidraga, a rebellious Dalmatian nobleman, and captured Domald's fortress at Klis. Domald's domains were confiscated and distributed among his rivals, the Šubići, who had supported Béla during the siege.
length_constraints:number_sentences[8]