The general picture of the history of Dutch Catholicism is that of a unified, hierarchic, ultra-montane subculture between 1870-1960 that was replaced for a liberal, open-minded, world-oriented identity after Vatican II. But in daily life, contrary to the official declarations, the Church and its members gradually adapted to modern society already after 1920. With the help of rational choice theory on religion, this shift from ‘sect’ to ‘church’ in this period will be highlighted. Catholics became ordinary citizens, changed their position (...) towards the national state and Catholic intellectuals introduced modern developments in the Catholic social organizations. By 1960, Catholics could no longer be discerned as different from the rest of society. The article therefore makes a plea to re-evaluate the period 1920-1960 from this perspective, also from an international perspective. (shrink)