After having described the historical basis of the process of pillarization in Belgium, the author explains the emergence of the Catholic pillar as a defence mechanism of the Catholic Church and the Catholic leadership to protect the Catholic flock from secularization. He describes the different services the Catholic pillar was offering for its members and the development of Belgium as a state based on three pillars: the catholic, the socialist and the liberal one that were all three institutionalized. This structure meant that Belgium was rather a segregated country that was vertically integrated. In the sixties of last century, the pillar was confronted with a growing secularization of the population, which forced the leadership of the pillar to adapt the collective consciousness: the Catholic credo, values and norms were replaced by so-called typical values of the Gospel integrated in what is called a Socio-Cultural Christianity. Under the impact of the changing economic situation, the politicization of the Flemish question and the emergence of Ecologist parties, the Christian pillar had to adapt its services and is now based on clienteles rather than members. Only in the Flemish part of Belgium is it still an institutionalized pillar.