The Ecclesiastical History Of Sozomenus by Sozomen
Chapter XV.--Constantine throws aside the Emblems of Imperial Power, and is ordained as Presbyter; his Subsequent Death. Death of the other Tyrants who had conspired against Honorius.
After this victory the troops of Honorius again laid siege to the city. When Constantine heard of the death of Edovicus he cast aside his purple robe and imperial ornaments, and repaired to the church, where he caused himself to be ordained as presbyter. Those within the walls, having first received oaths, opened the gates, and their lives were spared. From that period the whole province returned to its allegiance to Honorius, and has since been obedient to the rulers of his appointment. Constantine, with his son Julian, was sent into Italy, but he was waylaid and killed. Not long afterwards Jovianus and Maximus, the tyrants above mentioned, Saros, and many others who had conspired against Honorius, were unexpectedly slain.