The dissolution of the Soviet Union occurred between 1988 and 1991, and was the process of internal disintegration within the USSR, which began with growing unrest in its various constituent republics developing into an incessant political and legislative conflict between the republics and the central government, and ended when the leaders of three primal republics (the Russian SFSR, the Ukrainian SSR and the Byelorussian SSR) declared it no longer existed, later accompanied by 11 more republics, resulting in President Mikhail Gorbachev having to resign and what was left of the Soviet parliament formally acknowledging what had already taken place.