Career
Among the first things he witnessed was the beating to death of the indigenous ruler of Tacubaya by Diego Delgadillo for not being able to provide the latter with sufficient workers to construct his palace. He started to work closely with Fray Pedro de Gante, creating instructional materials for the natives. He missionized in Michoacán and in Atlixco before going to work among the Maya people of Yucatán and later among the Nahua people of Huejotzinco, where he spent the last part of his life in the monastery.
As he never became fluent in an indigenous language he invented a way of proselytizing with images called Testerian codices employing the rebus system to teach Indians Christian doctrine.