For a number of historical reasons, religious and national identity in Poland have over a long period become almost indistinguishable; nowhere else has the convergence been so strong (with the possible exception of Ireland). Since the definitive triumph of the Counter-Reformation in the 17th century, the Roman Church has enjoyed a virtually monopolistic position among ethnic Poles; the Lutheran and Calvinist communities have been reduced to tiny minorities (in the 16th century, Calvinism was well-established among the nobility); sectarian movements have not achieved any significant size; and Judaism has not become a spiritual rival to the Church as its influence was felt in a different social milieu. There were, of course, sceptics, atheists, anticlericals, freemasons and freethinkers, chiefly among the educated classes, and they grew in number. Yet until the second half of the 19th century Polish culture was emphatically Catholic. To be sure, some of the outstanding writers who in the 19th century contributed decisively to shaping the “Polish spirit” could not—by any standards—be counted among ultramontanist bigots: some were philosophically highly unorthodox, and anti-Roman or anticlerical views were by no means exceptional in their writings. Yet the profoundly Christian inspiration of their thought was undeniable and their work hardly affected the Catholic loyalty and fidelity of the faithful.
An erosion of faith was slowly taking place, however, among the Polish intelligentsia in the last decades of the 19th century, supported and stimulated by the social and intellectual forces that were operating all over Europe in the wake of growing urbanization and industrialization. The general spirit of the Enlightenment, positivism, and enthusiasm for science, combined with the idea of social progress and the secularization of morals inspired attacks on the Church for its obscurantism, parochialism, and enmity to human advancement. These attacks were part of the well-known patterns of conflict that were then tearing at the traditions in the Christian parts of the world. However, radical movements, socialist and agrarian, although often strongly anticlerical, could hardly be called anti-Christian, and the mordant militant atheism that did exist was but a marginal phenomenon in cultural life. At the outset of the 20th century Catholic modernism was not absent, but its influence was very weak compared with a country like France.