St. Callistus I (217-222) was one of the great popes of the third century. As a deacon he was charged with the administration of the Church’s property and with gathering together the bodies of the martyrs; he organized the famous cemetery on the Appian Way, called after him San Callisto. As pope he regulated the discipline of the sacrament of penance, and had to face the schism of Hippolytus. He was killed in a popular insurrection and has been honored as martyr since the seventh century.