The CIS has its origins with the Russian Empire, which was replaced in 1917 by the Russian Republic after the February Revolution earlier that year. Following the October Revolution, the Russian Soviet Federative Socialist Republic became the leading republic in the Soviet Union (USSR) upon its creation with the 1922 Treaty and Declaration of the Creation of the USSR along with Byelorussian SSR and Ukrainian SSR. When the USSR began to fall in 1991, the founding republics signed the Belavezha Accords on 8 December 1991, declaring that the Soviet Union would cease to exist and proclaimed the CIS in its place. A few days later the Alma-Ata Protocol was signed, which declared that the Soviet Union was dissolved and that the Russian Federation was to be its successor state. The Baltic states (Estonia, Latvia and Lithuania), which regard their membership in the Soviet Union as an illegal occupation, chose not to participate. Georgia withdrew its membership in 2008. Ukraine ended its participation in CIS statutory bodies on 19 May 2018.