Meanwhile, in 632 the Bulgars formed an independent state north of the Black sea that became known as Great Bulgaria under the leadership of Kubrat. Pressure from the Khazars led to the disintegration of Great Bulgaria in the second half of the 7th century. One of Kubrat's successors, Asparukh, migrated with some of the Bulgar tribes to the area around the Danube delta, and subsequently conquered Scythia Minor and Moesia Inferior from the Byzantine Empire, expanding his new kingdom further into the Balkan peninsula. The crucial Battle of Ongal in 680, the peace treaty with Byzantium in 681, and the establishment of a permanent Bulgarian capital at Pliska south of the Danube mark the beginning of the First Bulgarian Empire. The new state brought together Thracian remnants and Slavs under Bulgar rule, and a slow process of mutual assimilation began. In the following centuries Bulgaria established itself as a powerful empire, dominating the Balkans through its aggressive military traditions, which led to development of a distinct ethnic identity. Its ethnically and culturally diverse people united under a common religion, language and alphabet which formed and preserved the Bulgarian national consciousness despite foreign invasions and influences.