The early years of Basil's reign were dominated by civil wars against two powerful generals from the Anatolian aristocracy; first Bardas Skleros and later Bardas Phokas, which ended shortly after Phokas's death and Skleros's submission in 989. Basil then oversaw the stabilization and expansion of the eastern frontier of the Byzantine Empire and the complete subjugation of the First Bulgarian Empire, its foremost European foe, after a prolonged struggle. Although the Byzantine Empire had made a truce with the Fatimid Caliphate in 987–988, Basil led a campaign against the Caliphate that ended with another truce in 1000. He also conducted a campaign against the Khazar Khaganate that gained the Byzantine Empire part of Crimea and a series of successful campaigns against the Kingdom of Georgia.