Up to that date Julian had maintained a high reputation for ability, learning, and orthodoxy, and Mercator concludes that he must have sympathized with Innocent's condemnation of the Pelagians.
[3] When the cases of Pelagius and Coelestius were reopened by Zosimus, shortly after the death of Innocent, Julian seems to have expressed himself strongly in their favour in the hearing of Mercator; and when Zosimus issued his Epistola Tractoria 577 against the Pelagians (417 CE) and sent it to the major sees of the East and West for subscription, with the notable exception of Antioch, Julian was among those who refused.
The letter of Julian to Rufus, with another to the clergy of Rome which he denied to be his,[5] were answered by Augustine in his Contra Duas Epistolas Pelagianorum.
Julian avows an earnest desire to gain the aid of the Oriental bishops against the "profanity of Manicheans," for so he styles the Catholics;[11] accuses Zosimus of tergiversation and the Roman clergy of having been unduly influenced in their condemnation of the Pelagians;[12] charges both with various heresies;[13] and protests that by their means the subscriptions of nearly all the Western bishops had been uncanonically extorted to a dogma which he characterizes as "non minus stultum quam impium".
Augustine freely quotes his antagonist, and Julian again insisted upon the Manicheism of his opponents;[20] again charged Zosimus with prevarication,[21] and elaborated the whole anthropology for which he contended.
When driven from the West, Julian and some of his fellow-exiles went into Cilicia and remained for a time with Theodorus, bishop of Mopsuestia,[22] who is charged by Mercator with having been one of the originators of Pelagianism[23] and who wrote against Augustine.
On the death of Boniface I and the succession of Celestine I in September 422, Julian apparently left Cilicia and returned to Italy, probably hoping that the new pontiff might reconsider the case of the Pelagians, especially as a variance had then arisen between the Roman see and the African bishops.
[32] The patriarch wrote to Celestine more than once on his behalf and that of his friends,[33] but the favour he shewed them necessitated his defending himself in a public discourse delivered in their presence, and translated by Mercator.
[34] In 429 Mercator presented his Commonitorium de Coelestio to the emperor, wherein he carefully relates the proceedings against the Pelagians and comments severely upon their teaching.
[36] Whither he went from Constantinople does not appear, but he with other Pelagians seem to have accompanied Nestorius to the convent of Ephesus, 431 CE, and took part in the Conciliabulum held by John of Antioch.
[40] Julian attempted to recover his lost position through him, but Sixtus evidently treated him with severity, mainly at the instigation of Leo, then a presbyter, who became his successor, 440 CE.
[44] Garnier claims Julian as the translator of the Libellus Fidei a Rufino Palaestinae Provinciae Presbytero, which he has published in his edition of Marius Mercator,[45] and as the author of the liber Definitionum seu Ratiocinationem, to which Augustine replied in his de Perfectione Justitiae.
[46] A sympathetic and accessible account of Julian's Pelagian theology can be found in chapter 32 of Peter Brown's Augustine of Hippo: A Biography (1967, 2000).
From the year 419 on, Julian and St. Augustine waged a well-matched war of books, pamphlets, letters, and sermons from which we gain a clear idea of their contrasting views.
Adult baptism does remit sins, but for the Pelagian, this meant that the baptized Christian, after this dramatic fresh start, was now free to perfect himself alone, with or without the aid of the Church.