Béla III (, , ; 114823 April 1196) was
King of Hungary and
Croatia between 1172 and 1196. He was the second son of King
Géza II and Géza's wife,
Euphrosyne of Kiev. Around 1161, Euphrosyne granted Béla a duchy, which included
Croatia, central
Dalmatia and possibly
Sirmium. In accordance with a peace treaty between his elder brother,
Stephen III, who succeeded their father in 1162, and the
Byzantine Emperor Manuel I Komnenos, Béla moved to
Constantinople in 1163. He was renamed to
Alexios, and the emperor granted him the newly created senior
court title of
despotes. He was betrothed to the Emperor's daughter,
Maria. Béla's patrimony caused armed conflicts between the
Byzantine Empire and the
Kingdom of Hungary between 1164 and 1167, because Stephen III attempted to hinder the Byzantines from taking control of Croatia, Dalmatia and Sirmium. Béla-Alexios, who was designated as Emperor Manuel's heir in 1165, took part in three Byzantine campaigns against Hungary. His betrothal to the emperor's daughter was dissolved after her brother,
Alexios, was born in 1169. The emperor deprived Béla of his high title, granting him the inferior rank of
kaisar.