ally, Mihajlo Višević, who had seen a threat in Petar during the latter's conquest of Bosnia and Neretva, heard of the possible alliance and warned the Bulgarian Tzar, who later sent a protege, Pavle Branović, to rule Serbia. In the meantime, Zaharija Pribislavljević was sent by the Byzantines to take the Serbian throne, but he was captured by Pavle and sent to Bulgaria. Pavle was then approached by the Byzantines, and so Zaharija was persuaded by the Bulgarians to switch sides. Pavle planned an attack on Bulgaria, but Tzar Simeon was warned again, and dispatched Zaharija with an army, promising him the throne if he defeated Pavle, which he did. Zaharija soon resumed his Byzantine alliance, also uniting several Slavic tribes along the common border to revolt against the Bulgarians. Several Bulgarian generals were beheaded, their heads sent to Constantinople by Zaharija as a symbol of allegiance. In 924 a large Bulgarian army led by Časlav Klonimirović, the second cousin, ravaged Serbia, forcing Zaharija to flee. Instead of instating Časlav, however the Bulgarians annexed Serbia between 924 and 927. Prince Časlav took the throne in 927, with the death of the Bulgar Tzar, and immediately concluded an alliance with the Byzantine Empire. Eastern Orthodox influence greatly increased and Časlav maintained close ties with the Byzantines throughout his reign. He enlarged Serbia, uniting the tribes of Bosnia, Herzegovina, Old Serbia and Montenegro (which included Pagania, Zahumlje, Travunia, Konavle, Bosnia and Rascia into Serbia, ι Σερβλια). He took over regions previously held by Michael Višević, who disappears from the historical record in 925. The De Administrando Imperio describes his realm: the shores of the Adriatic Sea, the Sava river and the Morava valley as well as today's northern Albania. The written information about the first dynasty ends with the death of Časlav. Aftermath The Catepanate of Ras was established between 971 and 976, during the rule of John Tzimiskes (r. 969–976). A seal of a strategos of Ras has been dated to Tzimiskes' reign, making it possible that Tzimiskes' predecessor Nikephoros II Phokas was recognized in Rascia. The protospatharios and katepano of Ras was a Byzantine governor named John. Data on the katepano of Ras during Tzimiskes' reign is missing. Byzantine military presence ended soon thereafter with the wars with Bulgaria, and was re-established only ca. 1018 with the short-lived Theme of Sirmium, which, however, did not extend much into Serbia proper.