started to admit into the Church converts from sects or schisms who had not done penance. He fought with success the heretics, and established the practice of absolution of all sins, including adultery and murder. Hippolytus found Callixtus's policy of extending forgiveness of sins to cover sexual transgressions shockingly lax and denounced him for allowing believers to regularize liaisons with their own slaves by recognizing them as valid marriages. As a consequence also of doctrinal differences, Hippolytus was elected as a rival bishop of Rome, the first antipope. The Basilica di Santa Maria in Trastevere was a titulus of which Callixtus was the patron. In an apocryphal anecdote in the collection of imperial biographies called the Augustan History, the spot on which he had built an oratory was claimed by tavern keepers, but Alexander Severus decided that the worship of any god was better than a tavern, hence the structure's name. The 4th-century basilica of Ss Callixti et Iuliani was rebuilt in the 12th century by Pope Innocent II and rededicated to the Blessed Virgin Mary. The 8th-century Chiesa di San Callisto is close by, with its beginnings apparently as a shrine on the site of his martyrdom, which is attested in the 4th-century Depositio martyrum and so is likely to be historical. Death It is possible that Callixtus was martyred around 222 or 223, perhaps during a popular uprising, perhaps by being thrown down a well. According to the apocryphal Acts of Saint Callixtus, Asterius, a priest of Rome, recovered the body of Callixtus after it had been tossed into a well and buried Callixtus' body at night. Asterius was arrested for this action by the prefect Alexander and then killed by being thrown off a bridge into the Tiber River. Callixtus was buried in the cemetery of Calepodius on the Aurelian Way and his anniversary is given by the 4th-century Depositio Martirum and by subsequent martyrologies on 14 October. The Catholic Church celebrates his optional memorial on 14 October. His relics were transferred in the 9th century to Santa Maria in Trastevere. See also List of Catholic saints List of popes Pope Saint Callixtus I, patron saint archive Citations References Further reading András Handl (2014). Bishop Callistus I. of Rome (217?−222?): A Martyr or a Confessor? In Zeitschrift für Antikes Christentum/Journal of Ancient Christianity 18, p. 390-419. András Handl (2021). From Slave to Bishop. Callixtus’ Early Ecclesial Career