Estonian Soviet Socialist Republic

The Estonian Soviet Socialist Republic (Estonian SSR, ESSR), also known as Soviet Estonia, was a de facto administrative unit (union republic) of the former Soviet Union, established on the occupied and annexed territory of Estonia in 1940. It existed from 1940 to 1941 and again from 1944 until 1990, when the use of the name Estonian SSR was discontinued.

It was nominally established to replace the until then independent Republic of Estonia on 21 July 1940, a month after the 16–17 June 1940 Soviet military invasion and occupation of the country during World War II. After the installation of a Stalinistgovernment which, backed by the occupying Soviet Red Army, declared Estonia a Soviet constituency, the Estonian SSR was subsequently incorporated into the Soviet Union as a union republic on 6 August 1940. Estonia was occupied by Nazi Germany in 1941, until it was reconquered by the USSR in 1944.

Most of the world's countries did not recognise the incorporation of Estonia into the Soviet Unionde jure and only recognised its Soviet administrationde facto or not at all. A number of countries continued to recognise Estonian diplomats and consuls who still functioned in the name of their former government. This policy of non-recognition gave rise to the principle of legal continuity, which held that de jure, Estonia remained an independent state under occupation throughout the 1940–1991 period.

On 16 November 1988, Estonia became the first of the then Soviet-controlled countries to declare state sovereignty from the central government in Moscow. On 30 March 1990, the newly elected parliament declared that Estonia had been illegally occupied since 1940 and proclaimed a transitional period for the restoration of the country's full independence through Restitutio ad integrum. Subsequently, on 8 May 1990, the Supreme Soviet ended the use of the Soviet symbols as state symbols together with the name Estonian Soviet Socialist Republic and adopted Republic of Estonia as the official name of the state. Estonia was taking over and restored state institutions – on 1 August 1990, Estonia took over Soviet Ministry of Interior assets in Estonia; on 1 January 1990 Bank of Estonia was re-established; on 1 November 1990, the Estonian Border Guard; on 12 February 1991, Estonian Internal Security Service, on 1 March 1991 Estonian Police, and so on, eroding the occupation authorities in the state.

During the 1991 Soviet coup attempt the parliament of Estonia declared the re-establishment of full independence on 20 August 1991. The Soviet Union formally recognised the independence of Estonia on 6 September 1991. On 31 August 1994, the last remaining Russian troops left Estonia ending the era.