The societies of Western Europe, following the territorial delimitation of the corresponding State, have gone through different historical processes of internal homogenization. After the Peace of Westphalia (1648) the application of the principle cuius regio eius religio induced the religious homogenization of the population. Then, due to the ethnic diversity of its population, the State tried to homogenize it from the cultural point of view; it was the process of nationalization and democratization of the State. This process lead to the separation of religion from politics and from culture. After the two world wars, national reconstruction needed a foreign population: this need for labor was filled in the most developed countries by population of the countries that were least (Portuguese, Spanish, Italian ...) and also by population flows coming from the old colonies. The cultural and religious homogeneity of these countries began to lose force. With the oil crisis of the 1970s, a period of major economic fluctuations began in Europe. In those years, the second generation of the population of immigrant origin began to go to a job market that was not in good health. The religion and culture of their predecessors became autonomous resources for the reconstruction of their identity and to achieve a personal and social esteem. This process is necessarily leading States to rethink the relations between politics, culture and religion.