Ukraine was known as “Kievan Rus” up until sixteenth century. In the nineth century, Kiev was the big political and cultural center in the eastern Europe. Kievan Rus reached the height of its development in the 10th century and adopted by Vyzantine Christianity. Becouse of Mongol conquest in the 1240 year ended Kievan power. From the thirteenth to sixteenth century, Kiev was under the influence of Poland and western Europe. The negotiation of the Brest-Litovsk Union in 1596 year divided the Ukrainians into Orthodox and Ukrainian Catholic faithful. In 1654 year, Ukraine asked the king of Moscovy for protection against Poland, and the Treaty of Pereyasav signed that year recognized the suzerainty of Moscow. The agreement was interpreted by Her as an invitation to take in the Kiev, and the Ukrainian state was eventually absorbed to the Russian Empire.
  After the Russian Revolution, Ukraine declared its independence from Russia on Jan. 28, 1918 year, and several years of warfare ensued with several groups. The Red Army finally was victorious in the Kiev, and in 1920 year Ukraine became a Soviet republic. In 1922 year, Ukraine became one of the founders of the Union of Soviet Socialist Republics. In the 1930, the Soviet government's enforcement of collectivization met with peasant resistance, which in turn prompted the confiscation of the grain from Ukrainian farmers by Soviet authorities; the resulting famine took an estimated 5 million lives. Ukraine was one of the most devastated Soviet republics after World War II. On the April 26, 1986 year, the nation's nuclear power plant at Chernobyl was the site of the world's worst nuclear accident. On Oct. 29, 1991 year, the Ukrainian parliament voted to shut down the reactor within two years' time and asked for international assistance in dismantling it. When President Leonid Kravchuk was elected by the Ukrainian parliament in 1990, he vowed to seek Ukrainian sovereignty. Ukraine declared its independence on Aug. 24, 1991.