Religion forms a middle ground in culture and culture change. On the one hand, it is potentially as exchangeable and flexible as aesthetic principles, but on the other it often demands rigorous loyalty, and thus changes relatively little. We have noted, with regards to language change, how German Amish and Mennonites in Pennsylvania held on to German as their language because of the strictures of religion.
The period from about 1500 to the early nineteenth century was one of great religious turmoil throughout the Atlantic basin, but particularly in Christianity. In Europe, the Reformation tore the existing church order to pieces, and in its aftermath, intense theological debate coupled with emotionally charged religious war called long-held beliefs into doubt. Religious fundamentalists, both Protestant and Catholic, went to war with long-standing customs and practices.
The spread of Christianity from Europe to the Americas and, to a lesser extent, Africa is one of the singular features of the development of the Atlantic world, so that one could say that for much of the Atlantic, Christianity had become its religion, replacing or at least absorbing many others by 1800. Only in Africa was Christianity’s impact limited to a narrow wedge of Central Africa where the Kingdom of Kongo and the Portuguese colony of Angola were its adherents. Outside this larger area, only the Kingdom of Warri in the Niger Delta area (modern-day Nigeria) and scattered communities in West Africa, around Bissau (modern-day Guinea-Bissau) and in the immediate vicinity of the trading posts of various European colonies in Senegal, Sierra Leone, the Gold Coast (modern-day Ghana), and the Slave Coast (modern-day Togo, Republic of Benin, and western Nigeria) were part of a Christian community. Even as Christianity was spreading in Africa, at times, particularly in the Senegambian and Sierra Leone regions, Islam was also expanding, and the Christian coastal community met an emerging and increasingly militant Islamic wave moving south and west.