The medieval principality of Kiev was the origin of the Russian state, but from before it existed, the area we today call the Ukraine was as much a passageway as a destination: from the north, Vikings (who called themselves Rus) came down the rivers to trade and hunt for slaves; from the south, Byzantium sent missionaries and traders; and nomadic peoples from inner Asia, Scythians, various Turkish peoples, Tatars and Mongols periodically surged in from the East. Natives and descendants of previous invaders accommodated to these intrusions. They had to. Many, of course, died or were killed, but many more intermarried or converted to the customs, languages and religions of the most recent of the newcomers.
Historians often describe these accommodations in religious terms: in the vast steppe lands near the Sea of Azov, the Khazars, a Turkish people, converted to Judaism while the people living around Kiev, then a trading post on the Dnieper river, became Greek (Orthodox) Christians and most of the nomads converted to Islam. There was no single overarching political, religious or social Ukrainian authority, but the bosses, chief men or warlords of towns, districts and large estates constituted themselves a sort of primitive parliament, the veche, to negotiate with one another and with the titular rulers. For a brief period in the Twelfth century, under this arrangement and led by a major figure in early history, Vladimir II, Monomakh, "Kiev" dominated most of what today is the Russian Federation including what later became the Tsardom of Moscow, but it did not include all of what today is the Ukraine.
Kiev's sway was shattered within half a century, and in 1169 Kiev itself was sacked and burned by armies from northern Russian city-states. As the great Kievan-Russian historian Michael Florinsky wrote, "The Kievan chapter of Russia's history was closed." The center of "Russian" power moved north to the city-state of Vladimir in what had been a mainly Finnish area. The district's later major city and capital, Moscow, was then just a small trading post crowding around a wooden stockade that, burned, demolished and rebuilt, came to be known as the Kremlin. Then in the Thirteenth century the Mongols of Chingis Khan arrived.