Solidarity's influence led to the intensification and spread of anti-communist ideals and movements throughout the countries of the Eastern Bloc, weakening their communist governments. As a result of the Round Table Agreement between the Polish government and the Solidarity-led opposition, elections were held in Poland on 4 June 1989, in which the opposition was allowed to field candidates against the Communist Party—the first free elections in any Soviet bloc country. A new upper chamber (the Senate) was created in the Polish parliament and all of its 100 seats were contestable in the election, as well as one-third of the seats in the more important lower chamber (the Sejm). Solidarity won 99 of the 100 Senate seats and all 161 contestable seats in the Sejm—a victory that also triggered a chain reaction across the Soviet Union's satellite states, leading to almost entirely peaceful anti-communist revolutions in Central and Eastern Europe known as the Revolutions of 1989 ("Jesień Ludów" or "Wiosna Obywatelów"), which ended in the overthrow of each Moscow-imposed regime, and ultimately to the dissolution of the Soviet Union in the early 1990s.