Before becoming pope, Sixtus III was a leading Roman priest and corresponded with St Augustine. He was consecrated on 31 July 432, during the Nestorian and Pelagian (the teaching of Pelagius that people can be good without God's grace) controversies. His conciliatory nature probably led to false charges that he leaned toward those heresies.

As pope he approved the Council of Ephesus (the 431 worldwide council that declared Mary 'Mother of God') and worked to make peace between Cyril of Alexandria and John of Antioch. He refused to readmit the Pelagian Julian of Eclanum, and defended papal rights over Illyricum.

In Rome he restored the basilica now called St Mary Major and enlarged St Lawrence outside the Walls. The story that the consul Bassus accused him of a crime comes from a forgery. He died in 440.

Thin entry · the 1897 book gives only 76 words. We have not filled the gap with invented detail.

Saint Sixtus III. was a native of Rome.

Consecrated 31 July, 432; d. 440. Previous to his accession he was prominent among the Roman clergy and in correspondence with St. Augustine. He reigned during the Nestorian [Nestorius (d. c. 451), whose teaching split Christ into two persons; condemned at Ephesus in 431] and Pelagian [followers of Pelagius, who taught people could be good without God’s grace] controversies, and it was probably owing to his conciliatory disposition that he was falsely accused of leanings towards these heresies. As pope he approved the Acts of the Council of Ephesus and endeavoured to restore peace between Cyril of Alexandria and John of Antioch. In the Pelagian controversy he frustrated the attempt of Julian of Eclanum to be readmitted to communion with the Catholic Church. He defended the pope's right of supremacy over Illyricum against the local bishops and the ambitious designs of Proclus of Constantinople. At Rome he restored the Basilica of Liberius, now known as St. Mary Major, enlarged the Basilica of St. Lawrence-Without-the-Walls, and obtained precious gifts from the Emperor Valentinian III for St. Peter's and the Lateran [St. John Lateran, the pope’s cathedral in Rome] Basilica. The work which asserts that the consul Bassus accused him of crime is a forgery. He is the author of eight letters (in P.L., L, 583 sqq.), but he did not write the works "On Riches", "On False Teachers", and "On Chastity" ("De divitiis", "De malis doctoribus", "De castitate") attributed to him. His feast is kept on 28 March.

DUCHESNE (ed.), Lib. Pont., I (Paris, 1886), 126-27, 232-37; BARMBY in Dict. Christ. Biog., s. v. Sixtus (3); GRISAR, History of Rome and the Popes, tr. CAPPADELTA, I (St. Louis, 1911), nos. 54, 135, 140, 144, 154.