The Congress of Estonia was an innovative grassroots parliament established in Estonia as a part of the process of regaining of independence from the Soviet Union. It also challenged the power and authority of the pre-existing quasi-parliament in the country, called the Supreme Soviet of the Estonian SSR, which had been imposed on Estonia after Moscow's illegal annexation in 1940. The Congress of Estonia declared that it represented the highest authority on questions of Estonian statehood and citizenship, deriving this authority from the consent and initiative of the citizens of Estonia. The aim of the Congress was to restore Estonian independence based on the principle of legal continuity, with the pre-1940 republic of Estonia, which had been established in 1918, as the foundation.
In 1989, independence activists formed a mass movement called the Estonian Citizens' Committees (Estonian: Eesti Kodanike Komiteed) and started registering persons who were Estonian citizens by birth according to the jus sanguinis principle, i.e., persons who held Estonian citizenship in June 1940 (at which point Estonia's de facto structures of state were systematically dismantled and reorganized, after the country had been occupied by the Soviet Union), and their descendants. People who did not satisfy these criteria were invited to file applications for citizenship. By February 1990, 790,000 citizens and about 60,000 applicants had been registered.
In February 1990, the election of a body of representatives of these citizens – the Congress of Estonia – was conducted by those who had been registered. The Congress had 499 delegates from 31 political parties. The Estonian National Independence Party (Estonian: Eesti Rahvusliku Sõltumatuse Partei, usually abbreviated as ERSP) won the most seats. Other parties represented included the Popular Front of Estonia, the Heritage Society and the Communist Party of Estonia. The permanent standing committee of the Congress of Estonia – the Committee of Estonia (Estonian: Eesti Komitee) – was chaired by Mr. Tunne Kelam.