Many members of the clergy had cooperated with the anti-Bolshevik White Armies during the Russian civil war of 1918–22 and the Church was subject to severe persecution throughout the 1920s and 1930s, although Soviet figures estimate that one-third of the urban population and two-thirds of the rural population still held on to their religious beliefs. A new anti-ecclesiastical campaign was initiated post-World War II and it was not until the glasnost period of the late 1980s that some degree of religious tolerance returned. In the wake of World War II the Soviet Union extended its persecution of religion to the newly Communist eastern bloc. Many churches were closed, lost their prominence in public life, and children were taught atheism. Eventually, the religious authorities became champions of mass political dissent against the regime, both in the Protestant GDR and in Catholic Poland. Pope John Paul II (1920–2005), the first non-Italian pope since the 1520s, played a vital role in rallying Catholic opposition to communist regimes in the 1980s.