The Soviet Union (or more formally USSR – the Union of Soviet Socialist Republics) was established in 1922 as a federation of nationalities, which eventually came to encompass 15 major national territories, each organized as a Union-level republic (Soviet Socialist Republic or SSR). All 15 national republics, created between 1917 and 1940, had constitutionally equal rights and equal standing in the formal structure of state power. The largest of the 15 republics – Russia – was ethnically the most diverse and from the very beginning it was constituted as the RSFSR – the Russian Soviet Federative Socialist Republic, a federation within a federation. The Russian SFSR was divided in the early 1920s into some 30 autonomous ethnic territories (Autonomous Soviet Socialist Republics – ASSR and autonomous oblasts – AO), many of which exist to this day as ethnic republics within the Russian Federation. There was also a very large number of lower-level ethnic territories, such as national districts and national village soviets. The exact number of ASSR and AO varied over the years as new entities were created while old entities switched from one form to another, transformed into Union-level republics (e.g., Kazakh and Kyrgyz SSR created in 1936, Moldovan SSR created in 1940), or were absorbed into larger territories (e.g., Crimean ASSR absorbed into the RSFSR in 1945 and Volga German ASSR absorbed into RSFSR in 1941).