Since its emergence as an organized state, Russia has collided with the West. For over a millennium, the two have clashed economically, politically and militarily, using the countries that form the buffer between them as a staging ground for their rivalry. With Ukraine's Euromaidan uprising and Russia's subsequent annexation of Crimea in March 2014, the long-standing conflict has been renewed. But just as the end of the Cold War did not resolve hostilities between Russia and the West, neither will a resolution to the Ukrainian crisis erase the fundamental imperatives that have pitted the two against each other for more than a thousand years. The Russia-West divide began when the kingdom of Kievan Rus, the Slavic precursor to the modern Russian state, arose in Eastern Europe in the ninth century. With territory stretching from the Baltic Sea to the Black Sea, Kievan Rus was one of medieval Europe's largest states.