Géza II died on 31 May 1162. Lucas, Archbishop of Esztergom, crowned the 15-year-old Stephen king without delay. On hearing of Géza II's death, Emperor Manuel hastened towards Hungary, because he "put a high value on the overlordship" of the country, according to the Byzantine historian John Kinnamos. Another Byzantine historian, Niketas Choniates, wrote that the Emperor decided to support the young King's uncle and namesake, Stephen, to acquire the throne in the hope that "he might receive the undisputed and guaranteed possession" of Sirmium and Zimony (now Zemun in Serbia) from his protégé. When supporting the claim of the late King's brother to the crown, the Emperor referred to "the law of the Hungarians" which prescribed that the crown should pass "always to the survivors of brothers", according to Kinnamos. Emperor Manuel dispatched an army to Hungary which advanced as far as Haram (now Ram, Serbia) where his envoys opened negotiations with the Hungarian barons. Bribed by the Byzantines and fearful of an invasion by the Emperor, the magnates agreed to accept Ladislaus, who was the older of the young King's two uncles, as a "compromise candidate". The young Stephen's army was routed at Kapuvár. He fled from Hungary and sought refuge in Austria six weeks after his coronation. Archbishop Lucas was one of the few who remained loyal to the young monarch, refusing to crown his uncle. After Mikó, Archbishop of Kalocsa, performed Ladislaus's coronation, Archbishop Lucas even excommunicated the usurper, stating that he had unlawfully seized the crown from his nephew. Stephen III returned from Austria and captured Pressburg. He could not take advantage of his uncle's death on 14 January 1163, because Ladislaus II was succeeded by his younger brother, Stephen IV. However, Stephen IV's unveiled support for the interests of the Byzantine Empire caused discontent among the Hungarian barons. The young Stephen mustered an army of the barons who had deserted his uncle and supplemented it with German mercenaries. Stephen III defeated his uncle at Székesfehérvár on 19 June 1163. The elder Stephen was captured, but Stephen III released him upon the advice of Archbishop Lucas. The archbishop, along with the Dowager Queen Euphrosyne, remained the young monarch's principal advisors throughout his reign. The dethroned Stephen IV first fled to the Holy Roman Empire, but left shortly afterwards for the Byzantine Empire, where Emperor Manuel again promised him support. Wars with the Byzantine Empire (1164–1167)