Poland and the Holy Roman Empire concluded the Peace of Bautzen in January 1018. Later in the same year, 500 Hungarian horsemen accompanied Boleslav of Poland to Kiev, suggesting that Hungary had been included in the peace treaty. The historian Ferenc Makk says that the Peace of Bautzen obliged Boleslav to hand over all the territories he had occupied in the Morava valley to Stephen. According to Leodvin, the first known Bishop of Bihar (r. 1050 – 1060), Stephen allied with the Byzantines and led a military expedition to assist them against "barbarians" in the Balkan Peninsula. The Byzantine and Hungarian troops jointly took "Cesaries" which Györffy identifies as the present-day town of Ohrid. Leodvin's report suggests that Stephen joined the Byzantines in the war ending with their conquest of Bulgaria in 1018. However, the exact date of his expedition is uncertain. Györffy argues that it was only in the last year of the war that Stephen led his troops against the Bulgarians.