Treaty on the Creation of the USSR on 30 December 1922 by a conference of delegations from the Russian SFSR, the Transcaucasian SFSR, the Ukrainian SSR and the Byelorussian SSR. The Treaty and the Declaration were confirmed by the 1st Congress of Soviets of the USSR and signed by heads of delegations Mikhail Kalinin, Mikhail Tskhakaya, Mikhail Frunze and Grigory Petrovsky, Aleksandr Chervyakov respectively on December 30, 1922. The treaty provided flexibility to admit new members. Therefore, by 1940 the Soviet Union grew from the founding four republics to 15 republics. On 8 December 1991, Russian, Ukrainian and Belarusian Presidents signed the Belavezha Accords. The agreement declared
Treaty on the Creation of the USSR adjoined to the Soviet Union on 3, 5 and 6 August respectively. The final republic was the Moldovian SSR that merged the large territory of Bessarabia with the Moldovian ASSR previously part of the Ukrainian SSR. After World War II, no new republics were established, instead, the Karello-Finnish SSR was downgraded into an autonomous republic and re-annexed by the RSFSR on July 16, 1956. On December 8, 1991, the leaders of the Ukrainian and Belorussian SSRs, and the RSFSR met to agree on the annulment of the 1922 treaty, which was terminated on December 25, 1991, effectively dissolving the USSR.