Converting indigenous people to Christianity was one of the most important justifications for European expansion. The first missionaries to the New World accompanied Columbus on his second voyage, and more than 2,500 Franciscans, Dominicans, Jesuits and other friars crossed the Atlantic in the following century. Later French explorers were also accompanied by missionaries.

Catholic friars were among the first Europeans to seek an understanding of native cultures and languages as part of their effort to render Christianity comprehensible to indigenous people. They were also the most vociferous opponents of abuses committed by Spanish settlers.

Religion had been a central element of pre-Columbian societies, and many, if not all, indigenous people were receptive to the new religion that accompanied the victorious Iberians. In addition to spreading Christianity, missionaries taught indigenous peoples European methods of agriculture and instilled obedience to colonial masters. Despite the success of initial conversion efforts, authorities could not prevent the melding together of Catholic teachings with elements of pagan beliefs and practices.