The Soviet occupation of Latvia in 1940 refers, according to the European Court of Human Rights, the Government of Latvia, the United States Department of State, and the European Union, to the military occupation of the Republic of Latvia by the Soviet Union ostensibly under the provisions of the 1939 Molotov–Ribbentrop Pact with Nazi Germany. When World War II started in September 1939 with the German invasion of Poland, Latvia had already come under the Soviet sphere of influence in the Molotov–Ribbentrop Pact and its Secret Additional Protocol of August 1939.