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).
Religion in the Soviet Union
Soviet policy was particularly harsh toward the Ukrainian Greek-Catholic Church. Ukrainian Greek-Catholics came under Soviet rule in 1939, when western Ukraine was incorporated into the Soviet Union as part of the Nazi-Soviet Nonaggression Pact. Although the Ukrainian Greek Catholic Church was permitted to function, it was almost immediately subjected to intense harassment. Retreating before the German army in 1941, Soviet authorities arrested large numbers of Ukrainian Greek Catholic priests, who were either killed or deported to Siberia. After the Red Army reoccupied western Ukraine in 1944, the Soviet regime liquidated the Ukrainian Greek-Catholic Church by arresting its metropolitan, all of its bishops, hundreds of clergy, and the more active church members, killing some and sending the rest to labor camps. At the same time, Soviet authorities forced the remaining clergy to abrogate the union with Rome and subordinate themselves to the Russian Orthodox Church.