The Catholic Church during the Age of Discovery inaugurated a major effort to spread Christianity in the New World and to convert the indigenous peoples of the Americas and other indigenous peoples. The evangelical effort was a major part of, and a justification for, the military conquests of European powers such as Portugal, Spain, and France. Christian missions to the indigenous peoples ran hand-in-hand with the colonial efforts of Catholic nations. In the Americas and other colonies in Asia, and Africa, most missions were run by religious orders such as the Franciscans, Dominicans, Augustinians, and Jesuits. In Mexico, the early systematic evangelization by mendicants came to be known as the "Spiritual Conquest of Mexico".

Dum Diversas is a papal bull issued on 18 June 1452 by Pope Nicholas V. Addressed to Afonso V of Portugal, it recognized Portugal's rights to territories it had discovered along the West African coast, and the reduction of the infidels and non-Christians territories to perpetual vassals of the Christian monarch.