They were established by Franciscan friars under charter from the monarchs of the Spanish Empire and the government of the Viceroyalty of New Spain in a policy called Reductions to facilitate the conversion of Native Americans into Christianity.
The affected included the rich cultures and tribes of: many of the 21 distinct Puebloan groups; the Tiwa; the Navajo; and the Apache.
The missions also aimed to pacify resistance to the European invasion of the tribes' Pre-Columbian homelands and loss of traditions.
The missions introduced European livestock, fruits, vegetables, and small-scale industry into the Southwest region.
They also introduced European diseases to which native people had little or no acquired immunity.