Final answer:
Missionaries in the New World chiefly taught Christianity to indigenous populations, aiming for conversion and integration into colonial society, which sometimes led to cultural assimilation and resistance.
Step-by-step explanation:
The missionaries, particularly from the Spanish realms, primarily taught the fundamentals of Christianity to native populations in the New World. They were part of Spain's spiritual conquest to convert indigenous people and instruct them in the Christian faith. It wasn't just religious education on the agenda; the Spaniards were convinced that they were duty-bound to bring their European notions of civilization, including religious beliefs and practices. However, the goal was not just to teach but to convert and integrate the natives into the colonial society. While some missionaries like Dominican friar Bartolome de las Casas sought to understand and respect native cultures, many others enforced Spanish ideals and the Catholic faith with little regard for existing beliefs and practices. This resulted in a fusion of traditions as well as outright resistance, such as the Pueblo Revolt of 1680, showcasing the complexities of cultural assimilation and religious conversion during the colonization period.