The majority of Germans (60%) are Christians: about 30% belong to the Roman Catholic Church (concentrated in the south and west), the other 30 percent (concentrated in the north and east) to the Protestant Church. More than a third of the population has no religious affiliation, especially in East Germany, in the former GDR. The communist ideology of the GDR has postulated the disappearance of religion. The second largest religion is Islam with about 4 million adherents (about 5% of the population). The majority of Muslims in Germany are of foreign origin.