The opposition in Poland grew stronger in the 1980s, organizing strikes and protests that forced the communist government to sign an agreement in 1980 allowing for the creation of the Solidarity trade union led by Lech Wałęsa. Fearing the opposition, the government imposed martial law from 1981-1983 but changes could not be stopped. In 1989, facing continuing unrest, the government and opposition began Round Table Talks, marking the beginning of the end of communism in Poland.