In the early 10th century, Simeon the Great established a Bulgarian Empire that spanned the Balkan peninsula. While officially at peace with the Byzantines, the Bulgars turned a blind eye to Magyar raids of Byzantine territory, while the Byzantines covertly supported a rebellion against Simeon that created an independent Serbian state. This fragile peace persisted until the warlike Byzantine emperor Nikephoros II decisively defeated the Abbasid caliphate on his eastern borders. He then bribed Svyatoslav, the grand prince of the Kievan Rus, to attack Bulgaria. Svyatoslav proceeded to conquer the eastern Bulgarian Empire and imprison their tsar. The Bulgarian general (and later, tsar) Samuel inflicted a crushing defeat on Basil II in 986, and went on to conquer parts of Byzantine Greece. However, his reign would end with a disastrous defeat, and when Tsar Ivan Vadislav died laying siege to Durazzo in 1018, the Bulgars submitted to Byzantine rule.