One of the most important events that took place during the legal activity of the union was the 1st National Congress of Delegates of Solidarity organised in the autumn of 1981 in Gdańsk (precisely on 5–10 September 1980 and 26 September – 7 October). The congress above all ended the almost one-year-long process of selecting the authorities of the union and formulated a plan for the next period of its activities. But, apart from impact on the current functioning of the organisation, the congress also resulted in the adoption of a series of documents of broader significance. One of them was the Appeal of the 1st National Congress of Delegates of Solidarity to the working men of Eastern Europe passed on 8 September. Through the document, Poles directly appealed to other nations subjugated to communism. Although it was very hard for the text to reach its addressees, it infuriated the leaders of communist parties in the Soviet bloc. Workers in the USSR were forced to take part in rallies where the Appeal was condemned. Leonid Brezhnev considered it a provocation and an attempt at promoting the idea of Solidarity in the countries of the communist bloc. Anti-solidarity rallies were also organised in Bulgaria, Czechoslovakia and Hungary. Protest letters were being sent to Poland, and the Politburo of the Polish United Workers’ Party (Polska Zjednoczona Partia Robotnicza, PZPR) regarded the document passed in Gdańsk as “mad provocation aimed against the allies of Poland.”

Three months later, General Wojciech Jaruzelski, the First Secretary of the Central Committee of PZPR and prime minister of the Polish People’s Republic, imposed martial law in Poland. Solidarity was officially liquidated, and ten thousand activists were interned. And yet the union survived in the underground and led to the fall of communism in Poland Europe in 1989.

The 21 demands (or postulates) of the Committee were drawn up during the night of August 16/17, 1980 by a team composed of Andrzej Gwiazda, Joanna Gwiazda, Bogdan Lis, Alina Pieńkowska, Lech Wałęsa, and Bogdan Borusewicz, on the basis of the demands submitted by striking crews from all over the country. The postulates were published on panels of plywood hung above the main gate of the Gdańsk Shipyard. In 2003 the panels were added to UNESCO’s ‘Memory of the World’ listing (Cultural Heritage of Humanity programme).

The opening postulate called for the establishment of free labour unions. The further postulates demanded that the rights and freedoms guaranteed by the Constitution be observed, that repressions against those persecuted for their beliefs or convictions be discontinued, that political prisoners be released, and that communist-party privileges be abolished. This was complemented by a series of economic and social demands put forth in the aim of improving society’s living conditions.

August 31, 1980 saw the signing, on the premises of the Gdańsk Shipyard, of the agreement between the Inter-Factory Strike Committee, representing more than 700 factories, and the government delegation, whereby “independent self-governing trade unions” were established and the government committed itself to implementing the major demands. The communist authorities’ acceptance of the 21 postulates led to the emergence of the Independent, Self-Governing Labour Union “Solidarity” – Poland’s Solidarność.