Highlight the main stages in the history of the Bulgarian kingdom.

The first Bulgarian kingdom existed from the 7th century to the 11th (681-1018). Its history can be divided as pre-Christian and Christian. The founder of Bulgaria as a tribal union is Khan Kurbat. After the defeat from the Khazars, part of the tribe, led by Asparukh, went to the Balkans, where they conquered and recaptured Mizia from Byzantium and in its place founded the First Kingdom. The agreement on the payment of tribute by the Byzantines to the khan was the record of the beginning of the kingdom of Asparukh. In 865, Bulgaria adopts Christianity. Under Tsar Simeon, the state expanded as much as possible, but later, due to wars with Byzantium and Russia, it weakened and was conquered.