The Cariri region is the most isolated and poor part of the rural zone of the diocese of Campina Grande in the Paraiba state of Brazil. The Catholic Church has been present here for a relatively short time: 335 years. Moreover the region has an isolated context and this favors conservatism so that only fundamental changes have an impact. These facts make the Cariri an interesting region for a case study about how Catholicism develops. I distinguish five periods, which are described with religious key words and situated in the socio-cultural context. This classification is a schematization: different types of Catholicism often exist together. It is obvious that the dominant features of Catholicism change with time, but in the mainstream of the fifth period we see a small revolution. Now there are not only influences in the socio cultural context and factors in the Church itself that cause changes, but there are also influences of powerful newcomers, the evangelical churches. Their main impact is that many people have left the Catholic Church and are going to live their old faith in a new form. The Catholic Church is searching for adequate ways to respond to this phenomenon.