Coelestius a native of Ireland (or of Bretagne?) of noble birth. According to Marius Mercator (Commonitorium, 2), he was a law student at Rome when Pelagius arrived there. Embracing the views of Pelagius, he accompanied him in 408 (or 409) to Sicily, and in 411 to Africa. By his character and talents he succeeded, even better than Pelagius, in diffusing the views which they held in common. He was accused of heresy before the bishop of Carthage, A.D. 412, and condemned. He appealed to Rome; and on his way stopped at Sicily, and there spread his opinions very successfully. Thence it is supposed that he went to Ephesus, where he was ordained presbyter. In 417 Pope Zozimus, at Rome, was so far satisfied by the explanations of Coelestius that he recommended the African bishops to restore him. In 418 he was condemned by a synod at Rome, and went to the East for safety; but about 429 he was banished from Constantinople by order of the emperor. The Council of Ephesus condemned him A.D. 431. His later years are involved in obscurity. "He wrote a Confessio Fidei Zozimo Papae oblata, and various epistles and appeals, the substance of most of which can be gathered from the excerpts given by Augustine and Jerome; but none of his writings have come down to us entire. Coelestius was a man of pure morality, and more zealous and active (perhaps more honest) than Pelagius as a controvertist. Jerome says of him (in an epistle to Ctesiphon, A.D. 415), 'Although a scholar of Pelagius, he is yet leader and master of the whole host.'" — Cave, Hist. Lit. Anno 407, 1:246; Murdoch's Mosheim, Church History, N. Y., 3 vols., 1, 370; Wiggers, Augustinism and Pelagianism, Emerson's transl., p. 40 sq.; Schaff, History of the Christian Church, 3. § 147. SEE PELAGIUS.