B.B. Warfield :
“But Pelagianism did not so die as not to leave a legacy behind it. “Remainders of Pelagianism” soon showed themselves in Southern Gaul, where a body of monastic leaders attempted to find a middle ground on which they could stand, by allowing the Augustineian doctrine of assisting grace, but retaining the Pelagian conception of our self-determination to good. We first hear of them in 428, through letters from two laymen, Prosper and Hilary, to Augustine, as men who accepted original sin and the necessity of grace, but asserted that men began their turning to God, and God helped their beginning. They taught that all men are sinners, and that they derive their sin from Adam; that they can by no means save themselves, but need God’s assisting grace; and that this grace is gratuitous in the sense that men cannot really deserve it, and yet that it is not irresistible, nor given always without the occasion of its gift having been determined by men’s attitude towards God; so that, though not given on account of the merits of men, it is given according to those merits, actual or foreseen. The leader of this new movement was John Cassian, a pupil of Chrysostom (to whom he attributed all that was good in his life and will), and the fountain-head of Gallic monasticism; and its chief champion at a somewhat later day was Faustus of Rhegium (Riez).”