Against Manichaean dualism he had vindicated free will; but as against Pelagianism he taught the bondage of sinful man - a position accepted in the East but never welcome there, and not more than half welcome even in the West.
Within Calvinism itself Pelagianism was revived in Arminianism, which denied the irresistibility, and affirmed the universality of grace.
It seems not unlikely that Pelagianism had taken root among the Christian communities of Ireland, and it was found necessary to send a bishop to combat the heresy.
The British bishops had grown alarmed at the rapid growth of Pelagianism in Britain and sought the aid of the Gaulish church.
In the East (Council of Ephesus, 431) he was helped by the entanglement of Pelagianism with Nestorianism, just as in the West the ruin of Nestorian prospects was occasioned partly by dislike for the better known system of Pelagianism.
Meanwhile in the Western Church the subject of sin and grace, and the relation of divine and human activity in salvation, received especial attention; and finally, at the second council of Orange in 529, after both Pelagianism and semi-Pelagianism had been repudiated, a moderate form of Augustinianism was adopted,, involving the theory that every man as a result of the fall is in such a condition that he can take no steps in the direction of salvation until he has been renewed by the divine grace given in baptism, and that he cannot continue in the good thus begun except by the constant assistance of that grace, which is mediated only by the Catholic Church.
It may be added that after the Reformation Arianism was revived in Socinianism, and Pelagianism in Arminianism; but the conception of heresy in Protestantism demands subsequent notice.