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–European Union Association Agreement
Beginning in the late 18th century most of Ukraine was first part of the Russian Empire. Afterwards, Western Ukraine was part of the Austro-Hungarian Empire and then passed to the Second Polish Republic until the 1939 Soviet invasion of Poland. Ukraine then joined the Soviet Union (both the Russian SSR and the Ukrainian SSR united into the Soviet Union from 1922) until Ukraine declared independence from the Soviet Union on 24 August 1991. Independent Ukraine originally maintained strong ties with Russia, and as such Ukraine's economy became integrated with the Russian economy.