Religiosity in the postwar period and de-Christianization afterwards reached especially great proportions in Central Europe, whereas the religious revival in Central Europe after 1978 is unparalleled. Another distinguishing feature is the adaptation of church structure to conditions of totalitarianism by the `underground church'. Different interpretations of these features are examined. Secularization theory does not offer sufficient explanation, partly because totalitarianism counteracted sociocultural differentiation. The rational choice approach does not fit either, because both premodern attributes and the social confrontation with totalitarianism and the resulting bipolar arrangement of the sociocultural system contradicted market conditions. The best explanatory concept is found in acculturation which produced distinct patterns of religiosity in different age cohorts.