He was placed on the throne of Hungary by his father-in-law, Byzantine Emperor Manuel I. He succeded his brother Stephen III. He married: Marguerite daughter of King Louis VII of France and Constance (daughter of Emp Alfonso VII of Spain), and Agnes de Chatillon daughter of Renaud de Chatillon and Constance (daughter of Prince Bohemond of Antioch). He also married both a daughter of Byzantine Emperor Manuel I and Margaret Comnena, who was niece of Manuel I.