Ukrainian Soviet Socialist Republic
Eventually, after the creation of the Communist Party (Bolshevik) of Ukraine in Moscow, a third Ukrainian Soviet government was formed on 21 December 1919 that initiated new hostilities against Ukrainian nationalists as they lost their military support from the defeated Central Powers. Eventually, the Red Army ended up controlling much of the Ukrainian territory after the Polish-Soviet Peace of Riga. On 30 December 1922, along with the Russian, Byelorussian, and Transcaucasian republics, the Ukrainian SSR was one of the founding members of the Union of Soviet Socialist Republics (USSR).
Ukraine
Following the death of Stalin in 1953, Nikita Khrushchev became the new leader of the USSR. Having served as First Secretary of the Communist Party of Ukrainian SSR in 1938–49, Khrushchev was intimately familiar with the republic; after taking power union-wide, he began to emphasize "the friendship" between the Ukrainian and Russian nations. In 1954, the 300th anniversary of the Treaty of Pereyaslav was widely celebrated. Crimea was transferred from the Russian SFSR to the Ukrainian SSR.