who were hoping to take advantage of the turmoil but was unable to capture the Strategos (military governor) of Theodosiopolis, who joined the rebellion and attempted to capture Thessalonica. Foreign and military affairs In terms of military affairs, Michael's reign began poorly. The Arabs sacked Myra, the Serbs threw off Byzantine authority and the Pechenegs raided almost at will up to the gates of Thessalonica. The situation was soon stabilised: on the eastern frontier, Arab pirates were either captured or killed; the Byzantines captured the Muslim fortress of Berkri, on the eastern shore of Lake Van; Edessa was relieved after a long siege and eventually ceded to the empire in 1037. On the western front, Michael and John ordered the general George Maniakes to conquer the Emirate of Sicily. In 1038 Maniakes landed in southern Italy and soon captured Messina. He then defeated the scattered Arab forces and captured towns in the west and south of the island. By 1040 he had stormed and taken Syracuse. He almost succeeded in driving the Arabs from the island, but Maniakes then fell out with his Lombard allies, while his Norman mercenaries, unhappy with their pay, abandoned the Byzantine general and raised a revolt on the Italian mainland, resulting in the temporary loss of Bari. Maniakes was about to strike against them when he was recalled by John the Eunuch on suspicion of conspiracy. After Maniakes's recall, most of the Sicilian conquests were lost and an expedition against the Normans suffered several defeats, although Bari was eventually recaptured. In the north, Pecheneg pressure had initially forced the Serbs to seek the protection of the Byzantine Empire and acknowledge Byzantine authority. In 1040 the Serbs again revolted, as did the Bulgarians. This uprising was partly caused by the heavy taxation in coin (and not, as before, in kind) imposed on Bulgaria by John's policies. It also aimed at the restoration of the Bulgarian state under the leadership of Peter Delyan. The rebels seized Belgrade, proclaimed Delyan Emperor of Bulgaria and then quickly took Scupi. Michael IV made things worse by removing from command the doux of Dyrrhachium, who had been marching against Peter Delyan, accusing him of a conspiracy. His troops, largely Bulgarian, joined the revolt and Delyan laid siege to Thessalonica. Dyrrhachium had been lost and Delyan defeated the Strategos of Hellas. Most of the theme of Nicopolis had risen up against Michael,