As the Byzantine-Bulgarian relations deteriorated by the end of the 960s, the Eastern Roman Empire paid the Kievan prince Sviatoslav to attack Bulgaria. The unexpected collapse of Bulgaria and Siatoslav's ambitions to seize Constantinople caught the Eastern Roman Empire off-guard but they managed to pull back the Kievan armies and occupied eastern Bulgaria including the capital Preslav in 971. Emperor Boris II was captured and taken to Constantinople where he abdicated and the Byzantine Emperor John I Tzimiskes announced the annexation of Bulgaria, even though the Eastern Roman Empire only controlled Eastern Bulgaria at the time, but the lands to the west remained under Bulgarian control. The four brothers David, Moses, Aron and Samuel of the Cometopuli dynasty ruled in the free territorie