before returning to Hungary. In early 1155, the Byzantine and Hungarian envoys signed a new peace treaty. In the same year, a Byzantine army expelled Géza's ally, Desa, from Serbia and restored Uroš II, who had promised that he would not enter into an alliance with Hungary. Last years (1155–1162) Frederick Barbarossa, who had been crowned Holy Roman Emperor, received the envoys of Manuel I in Nuremberg in July 1156. The Byzantine envoys proposed a joint invasion of Hungary, but Barbarossa refused their offer. On 16 September, Barbarossa stipulated that the dukes of Austria were to support the Holy Roman emperors during a war against Hungary in his charter by which he elevated Austria to a duchy, showing that the relationship between Hungary and the Holy Roman Empire was still tense. Barbarossa's close advisor, Daniel, Bishop of Prague, visited Hungary in the summer of 1157. On this occasion, Géza promised that he would support Barbarossa with auxiliary troops if the emperor invaded Italy. Géza's youngest brother, Stephen, started conspiring with their uncle, Beloš, and other lords against Géza, according to the nearly contemporaneous Rahewin. To avoid a civil war, Géza first ordered the persecution of Stephen's partisans, then had his rebellious brother expelled from the kingdom and even sentenced to death. Niketas Choniates also recorded that Stephen had been "forced to flee from the murderous clutches" of Géza. Géza's uncle, Beloš, was not mentioned in royal charters issued after March 1157, which suggest that he left Hungary after that date. During the summer of that year, Stephen fled to the Holy Roman Empire, seeking Emperor Frederick's protection against Géza. Upon the emperor's demand, Géza accepted Frederick Barbarossa as arbitrator in his conflict with Stephen and sent his envoys to Regensburg in January 1158. However, Barbarossa "decided to defer to a more suitable time the settlement" of the quarrel between Géza and Stephen and departed for his campaign against the Lombard League. In accordance with his former promise, Géza sent a troop of 5–600 archers to accompany the emperor to Italy. Before long, Géza's brother, Stephen, left for the Byzantine Empire and settled in Constantinople where he married Emperor Manuel's niece Maria Komnene. Within two years, he was joined by his brother, Ladislaus, who fled from Hungary around 1160. Frederick Barbarossa forced the Italian towns to surrender in September 1158. However, Milan and Crema again rose up in open rebellion against