This early-16th century manuscript, known as a Testerian catechism, is one of the more notable documents in the archives of the Center for the Study of the History of Mexico. In the early period of the Spanish conquest of Mexico, before religious instructors had learned the languages of the indigenous peoples, they used pictorial stories describing basic teachings to spread the Christian Gospel. These catechisms were called Testerians, after Father Jacobo de Testera, a Franciscan priest who pioneered this method of teaching. Catholic Church; Franciscans; Jacobo de Testera; Religious books