Many ethnically diverse peoples have migrated onto the East European Plain, but the East Slavs remain and gradually become dominant.

Kievan Rus', the first East Slavic state, emerges in the ninth century CE and develops a complex and frequently unstable political system that will flourish until the thirteenth century, when it declines abruptly.

Among the lasting achievements of Kievan Rus are the introduction of a Slavic variant of the Eastern Orthodox religion and a synthesis of Byzantine and Slavic cultures.

The disintegration of Kievan Rus' will play a crucial role in the evolution of the East Slavs into the Russian, Ukrainian, and Belorussian peoples.