The Byelorussian Soviet Socialist Republic (abbreviated as Byelorussian SSR or BSSR) (Belarusian: Беларуская Савецкая Сацыялістычная Рэспубліка [БССР] Belaruskaya Savetskaya Satsyyalistychnaya Respublika [BSSR]; Russian: Белору́сская Сове́тская Социалисти́ческая Респу́блика [БССР] Belorusskaya Sovetskaya Sotsalisticheskaya Respublika [BSSR]) was one of fifteen constituent republics of the Soviet Union. It was one of the four original founding members of the Soviet Union in 1922, together with the Ukrainian SSR, the Transcaucasian SFSR and the Russian SFSR. The Soviet Republic, along with the Ukrainian SSR and the Soviet Union, were founder members of the United Nations Organization in 1945.