The medieval state of Kievan Rus’ took shape in the late 10th century when Vladimir (Volodimer), reportedly a descendant of the semi-legendary Ri͡urik, established his exclusive rule over the Slavs, Finns, and Balts dwelling along the river systems stretching from the southern end of Lake Ladoga to Kiev (Kyiv) and adopted Christianity from Byzantium for his realm. His descendants, collectively known as the Riurikid dynasty, oversaw the growth of Kievan Rus’ into a complex federation of principalities, populated mainly by sedentary agriculturalists but also benefiting from urban commerce linked to broad intercontinental trade networks. Riurikid princes repeatedly competed with each other and also contended with nomads of steppe, especially the Pechenegs, Polovt͡sy (Kipchaks, Cumans), and the Mongols who conquered both the nomads of the Pontic steppe and the Rus’ principalities in 1237–1240.
Over the next century the western portions Kievan Rus’, located in modern Ukraine, Belarus, and Russia, were absorbed by Poland and Lithuania. Its northern principalities continued to be ruled by their Riurikid princes under the hegemony of the khans of the Golden Horde, the portion of the Mongol Empire more accurately known as Juchi’s ulus. As the Golden Horde fragmented in the 15th century, those principalities coalesced to form Muscovy, the precursor of modern Russia. Muscovite rulers expanded their realm by seizing territories from Lithuania and in the mid-16th century by annexing the Tatar khanates of Kazan’ and Astrakhan’, two heirs of the Golden Horde. By the time Riurikid dynastic rule ended in 1598, Muscovy had also subdued the Khanate of Sibir’, launching a new phase of development arising from its exploration and incorporation of Siberia and resulting in its transformation from a regional power into a vast Eurasian empire.