As the Byzantine-Bulgarian relations deteriorated Cause_change_of_position_on_a_scale by the end of the 960s , the Eastern Roman Empire paid Commerce_pay the Kievan prince Sviatoslav to attack Attack Bulgaria .

The unexpected collapse Destroying of Bulgaria and Sviatoslav 's ambitions to seize Conquering Constantinople caught Self_motion the Eastern Roman Empire off-guard but they managed to pull Motion back the Kievan armies and occupied Control eastern Bulgaria including the capital Preslav in 971 .