St. Dominic, by El Greco

As a young man Dominic entered an observant community of Augustinian monks and took up the work of combatting the Albigensian heresy. Later he founded the Dominican Order. It was Dominic's intention to make this order an instrument for the extirpation of heresy through the cultivation of exemplary asceticism, study, teaching, and preaching. Like the Franciscans, the Dominicans also adopted the practice of poverty and mendicancy. Study and teaching, however, became the enduring hallmarks of the order, and its members were known as the "watchdogs of orthodoxy." Many of the leading theologians of the late middle ages, including Thomas Aquinas, were Dominicans. Noted for devotion to orthodoxy and its enforcement, Dominicans were often assigned special tasks by the medieval popes, including the preaching of crusades, the prosecution of the Inquisition, and foreign mission.