The nation’s modern history began with that of the East Slavs. From at least the IX century, the territory of Ukraine was a centre of the medieval East Slavic civilization. This state, known as the Kievan Rus’ became the largest and most powerful nation in Europe, but disintegrated in the XII century. From the XIV century on, the territory of Ukraine was divided among a number of regional powers, and by the XIX century, the largest part of Ukraine was integrated into the Russian Empire, with the rest under Austro-Hungarian control. After a chaotic period of incessant warfare and several attempts at independence (1917–21) following World War I and the Russian Civil War, Ukraine emerged in 1922 as one of the founding republics of the Soviet Union. The Ukrainian Soviet Socialist Republic’s territory was enlarged westward shortly before and after World War II, and again in 1954 with the Crimea transfer. In 1945, the Ukrainian SSR became one of the co-founding members of the United Nations. Ukraine became independent again after the dissolution of the Soviet Union in 1991. This began a period of transition to a market economy, in which Ukraine was stricken with an eight year recession. But since then, the economy has been experiencing a stable increase with GDP growth averaging 24 percent annually.