How secure was the USSR´s control over Eastern Europe, 1948-c. 1989?: Solidarity

On 17 April 1989, Solidarity was again legalized and the union was allowed to field candidates in upcoming elections. Tadeusz Mazowiecki, a member of solidarity, was elected as Prime Minister of Poland. He became the first non-Communist Prime Minister in Poland since 1945. Under Mazowiecki a Solidarity-led government was formed.