Simeon I of Bulgaria
After several failures to capture the throne by other Vlastimirovićs, including the one backed by the Bulgarians, Tsar Simeon I of Bulgaria recognized Petar as ruler. He was put under Simeon's protection, resulting in a twenty-year peace and the Serbian-Bulgarian alliance (897–917). Petar was probably not happy with his subordinate position, and may have dreamed of reasserting his independence; his situation and the succession wars of the three branches of Vlastimir's sons were to play key parts in the coming Bulgarian-Byzantine War.