The Catholic missionaries who first brought Christianity to New Spain (colonial Mexico) were often very creative and innovative in their teaching methods. They used various audiovisual devices and, often without realizing it, built on preconquest and pre-Christian concepts, a form of unconscious syncretism. It is widely accepted that the missionary enterprise began in 1524 with the arrival of “The Twelve,” the first Franciscan missionaries. Their initial decision that evangelization would be carried on in the native languages, not Spanish, was crucial and had become Church policy by the eighteenth century. They were aided in this by the fact that Nahuatl, the Aztec language, served as a lingua franca, especially in commerce and diplomacy, throughout the central plateau and as far south as Guatemala. The Franciscans, and later the Jesuits, produced grammars (artes), dictionaries, sermonaries, catechisms, miracle stories, and even religious drama in Nahuatl. The adaptation of Nahuatl to the Latin alphabet was enthusiastically received by the native peoples who left us chronicles, town council records, censuses (with valuable information on baptisms and polygamy), lawsuits, and other documentation. With all this, we have been able to open a new window on colonial life.