During the age of exploration the Spanish destroyed countless indigenous temples in order to build thousands of Catholic missions throughout the Spanish empire. The purpose of this vast building program was to create a new Christian Utopia in the New World. Most Spanish missions followed the pattern established by Mexico's first viceroy, Antonio de Mendoza, in the sixteenth century. Thus all missions included a church, friary, atrium, and some type of outdoor chapel. Often missions were intentionally constructed on top of preexisting native religious structures.

The Franciscan mission of St. Michael the Archangel at Huejotzingo, Puebla, Mexico, is typical. Built in the 1550s by Native Americans under the direction of friar-architects, it defines the fortress church type. Fortress churches tower over the landscape in order to impress the native population with the power of Christianity. They may have also served as refuges in...