The Gdansk accords were signed on August 31, 1980, between the communist government and striking workers along the Baltic coast. The accords allowed a free trade union, the right to strike, and pay rises. They also limited censorship, freed political prisoners, and permitted the weekly broadcast of Catholic Mass on state-controlled radio and television.
Based on these accords, the Solidarity trade union was formally recognized on October 24 and eventually grew to a membership of 10 million Poles -- more than one-quarter of the country's population.
If you are really lucky I'll post this evening about the role of the Accords in toppling communism in Poland.