Zaharija was sent in 920 by Romanos I Lekapenos (r. 920–944) to retake the throne (as the rightful prince)[7] but was captured by Pavle and sent to Symeon in Bulgaria.

[5] Symeon was interrupted during the campaign[8] and was warned; he spared a few troops, sending them with Zaharija, and promising him the throne if he would defeat Pavle.

[5] Zaharija, who had long lived in Constantinople where he had been heavily influenced by the Byzantines, probably resented the Bulgarians after his capture, and was not truly won over.

[5] It was natural that the Serbs were pro-Byzantine and anti-Bulgarian; the Byzantines were distant and offered greater independence, while powerful Bulgaria interfered with its neighbour.

In 923, Symeon sent an insufficient number of troops to quell the rebels; several Bulgarian generals were killed, and their heads and weapons were sent by Zaharija as gifts to the Byzantines.

[5][9][10] It was after Symeon tried and failed to ally himself with the Fatimids in a naval siege on Constantinople, and when he lost the battle against Zaharija, that he decided to meet with Romanus.

[12][13] Symeon summoned all the Serbian dukes to pay homage to their new prince, but, instead of instating Časlav, he took them all captive, and annexed Serbia.

[11] Bulgaria now considerably expanded its borders, neighbouring its ally Michael of Zahumlje and Croatia, where Zaharija was exiled.