Ukrainian Soviet Socialist Republic
The Ukrainian Soviet Socialist Republic (Ukrainian SSR or UkrSSR or UkSSR; , УРСР ; , УССР ; see "Name" section below), also known as the Soviet Ukraine, was one of the constituent republics of the Soviet Union from the Union's inception in 1922 to its breakup in 1991. The republic was governed by the Communist Party of Ukraine as a unitary one-party socialist soviet republic.
Ukrainian People's Republic
The Ukrainian People's Republic, or Ukrainian National Republic (abbreviated to ', '), a predecessor of modern Ukraine, was declared on 10 June 1917 following the February Revolution in Russia. It initially formed part of the Russian Republic, but proclaimed its independence on 25 January 1918. During its short existence the republic went through several political transformations - from the socialist-leaning republic headed by the Central Council with its general secretariat to the national republic led by the Directorate and by Symon Petliura. Between April and December 1918 the Ukrainian People's Republic did not function, having been overthrown by the Ukrainian State of Pavlo Skoropadsky.
From late 1919 the UNR operated as an ally of the Second Polish Republic, but by then the state "de facto" no longer existed in Ukraine. The 18 March 1921 Treaty of Riga between the Second Polish Republic, Soviet Russia (acting also on behalf of Soviet Belarus) and of Soviet Ukraine sealed the fate of the Ukrainian People's Republic.