Religious missions were an important part of the northern frontier of New Spain. From seventeenth century to the early nineteenth century, the Roman Catholic Church built missions throughout what is now northern Mexico and the southwestern United States. The Spanish empire desired the gold and silver in the northern frontier, but they needed a well-established colonial system to extract them. The missionaries were the first to enter the frontier zones in an attempt to convert native populations to Christianity.
The Roman Catholic orders built hundreds of missions in New Spain; elaborate cathedrals and others simple churches. They erected hundreds of churches in the northern frontier but were eventually expelled by the Spanish government in 1767. Following the expulsion, the Franciscans and Dominicans took control of many of the former Jesuit missions.
After Mexico won its independence from Spain in 1821, the church and its structures took a secondary position to the growing towns and communities, and some mission buildings were converted for other uses.
Today, however, many mission sites remain essential to religious practices and civic activities in these communities. The Missions Initiative aims to support these active sites as well as build broader support for all sites and among all categories of stakeholders.
Source: History of Spanish Colonial Missions
missions.arizona.edu at The University of Arizona