Before considering the mainline or historical churches, a word must be said about American slave Christianity which is the matrix of a large part of Liberian Christianity. Of the slaves transported to the United States, initially very few converted to Christianity. For one thing, many slave owners refused to allow their slaves to be evangelised, fearing the impact on them of Christian emphases like compassion or freedom. Many slave owners who exposed their slaves to Christianity made sure that the kind of Christianity they were exposed to emphasised service, obedience and submission. The missionaries who promoted the idea of Christianity for slaves had a strong element of self-interest; they argued that slaves who were Christians would work harder, be more respectful and content than those without Christianity. Many slaves understood full well the reasons why whites urged Christianity on them, and rejected it accordingly.

However, in the early nineteenth century, there was a tremendous increase in the number of slaves accepting Christianity. This Christianity had obvious African roots; all commentators note its large element of voodoo or conjure, which was the great rival to evangelical Protestantism among the slaves. Numerous accounts relate the importance of the conjuror, particularly his supposed ability to wrest from the slave owner reduction of work or mitigation of punishment; sometimes his esteem among fellow slaves lay in his ability to have himself excused from all work.