Background of the occupation and annexation of the Baltic states

The background of the occupation of the Baltic states covers the period before the first Soviet occupation on 14 June 1940, stretching from independence in 1918 to the Soviet ultimatums in 1939–1940. The Baltic states gained their independence during and after the Russian revolutions of 1917; Lenin's government allowed them to secede. They managed to sign non-aggression treaties in the 1920s and 1930s. Despite the treaties, the Baltic states were forcibly incorporated into the Soviet Union in 1940 in the aftermath of the German–Soviet pact of 1939.

The Russian Empire acquired the Baltic areas as autonomous Duchies administered by Baltic German nobility via the Treaty of Nystad in 1721 and Courland in 1795. In 1914, World War I broke out and by 1915 German armies had occupied Lithuania and Courland incorporating the areas into Ober Ost. As the Russian Empire began to collapse, independence movements sprung up on many regions. After the 1917 October Revolution in Russia, Baltic political leaders attempted to establish the independent states of Estonia, Latvia and Lithuania; however, German control continued throughout the area until early 1918. Later in 1918, the area was drawn into the Russian Civil War and proclamations of independence were issued in Lithuania on 16 February, in Estonia on 24 February and in Latvia on 18 November 1918.

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