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
Poland defeated Western Ukraine in the Polish-Ukrainian War, but failed against the Bolsheviks in an offensive against Kiev. According to the Peace of Riga, western Ukraine was incorporated into Poland, which in turn recognised the Ukrainian Soviet Socialist Republic in March 1919. With establishment of the Soviet power, Ukraine lost half of its territory to Poland, Belarus and Russia, while on the left bank of Dniester River was created Moldavian autonomy. Ukraine became a founding member of the Union of Soviet Socialist Republics in December 1922.