The Khazar empire has reached the peak…

The Khazar empire has reached the peak of its power by the second half of the eighth century, extending along the northern shore of the Black Sea from the lower Volga and the Caspian Sea in the east to the Dnieper River in the west.

The main source of revenue for the empire stems from commerce and particularly from Khazar control of the east-west trade route that links the Far East with Constantinople and the north-south route linking the Arab empire with northern Slavic lands.

The Khazars control and exact tribute from the Alani and other northern Caucasian peoples dwelling between the mountains and the Kuban River; from the Magyars (proto-Hungarians) inhabiting the area around the Donets River; from the Goths; and from the Greek colonies in the Crimea.

The Volga Bulgars and numerous Slavic tribes also recognize the Khazars as their overlords.