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).
Volhynia
Soviet Ukraine annexed Volhynia after the end of World War II. In 1944 the communists in Volyhnia suppressed the Ukrainian Catholic Apostolic Exarchate. Most of the remaining ethnic Polish population were expelled to Poland in 1945. Since the dissolution of the Soviet Union in the 1990s, Volhynia has been an integral part of Ukraine.