In the middle of the seventh century, when the Slavs were in the course of penetrating the Russian forest on their eastward migration, the Black Sea steppe fell under the control of the Khazars, a Turkic nation from Inner Asia. Unlike the other Turkic groups of the time the Khazars did not pursue an exclusively nomadic mode of life centred on cattle breeding, but settled down to cultivate the soil and to trade. The main artery of their commerce was the Volga, which they controlled as far north as it was navigable. Using this route, they shipped luxury goods obtained from the Levant to trading posts in the forest populated by Ugro-Finnic peoples where they exchanged them for slaves, furs and various primary and semi-finished raw materials. By the end of the eighth century, the Khazars established a powerful state or kaganate extending from the Crimea to the Caspian and northward to the mid-Volga. At this time, the ruling elite, probably under the influence of Jewish colonists from the Crimea, were converted to Judaism. The kaganate's military power shielded the Black Sea steppe from Asiatic nomads, and enabled the early Slavic migrants to gain a precarious foothold in the black earth region. During the eighth and ninth centuries, the Slavs in the steppe and adjoining forest paid tribute to the Khazars and lived under their protection.
The little that is known of Eastern Slavs during this period (the seventh to ninth centuries) suggests that they were organized into tribal communities. The prevailing agricultural technique in the forest zone, where most of them resided, was 'slash-burn', a primitive method well suited to the conditions under which they then lived. Having made a clearing in the woods and hauled away the logs the peasants set the stumps and brush on fire. The ashes deposited after the flames had died down were so rich in potash and lime that seeds could be sown directly on the ground with a minimum of soil preparation. The soil treated in this manner yielded a few good harvests; as soon as it became exhausted, the peasants moved on to repeat the procedure in another