Final answer:
Catholic missionaries, especially the Jesuits, were successful in converting indigenous people due to their respect for indigenous customs and flexible approach to religious conversion.
Step-by-step explanation:
The key factor in the success of Catholic missionaries in converting indigenous people was their practice of cultural accommodation and their willingness to accept partial adoption of Christianity by indigenous people, rather than insisting on complete conversion and abandonment of their native beliefs. Catholic missionaries, particularly the Jesuits, respected indigenous customs and provided education, helping to bridge the gap between the two societies. They focused on the conversion to Catholicism without forcing other aspects of European culture, which was often met with resistance from native populations when tried by other religious groups.