 In the Eastern and Southeastern parts of Europe formatted dominant Barbarian states as the Hunnic Empire (370–469), the Avar Khaganate (567–after 822), Old Great Bulgaria (632–668), the Khazar Khaganate (c. 650–969), Bulgaria (founded by Asparuh in 680), Volga Bulgaria (7th century–1240s) and Kievan Rus' (879–1240), all of them constantly rivaling the hegemony of the Byzantine Empire and the rest of Europe.The barbarian kingdoms marked the transition from Late Antiquity to the Early Middle Ages in the 6th and 7th centuries, gradually replacing the Roman system of government on the lands of the Western Roman Empire, notably in the two western prefectures of Gaul and Italy.These kingdoms were "" of the Roman Empire, and even after the fall of the Western Roman Empire in AD 476 they continued to at least nominally consider themselves subject to the Eastern Emperor.