This from New Advent, regarding Pelagius:
<<<<<Pelagius denied the primitive state in paradise and original sin, insisted on the naturalness of concupiscence and the death of the body, and ascribed the actual existence and universality of sin to the bad example which Adam set by his first sin. As all his ideas were chiefly rooted in the old, pagan philosophy, especially in the popular system of the Stoics, rather than in Christianity, he regarded the moral strength of man’s will, when steeled by asceticism, as sufficient in itself to desire and to attain the loftiest ideal of virtue. The value of Christ’s redemption was, in his opinion, limited mainly to instruction and example which the Saviour threw into the balance as a counterweight against Adam’s wicked example, so that nature retains the ability to conquer sin and to gain eternal life even without the aid of grace. By justification we are indeed cleansed of our personal sins through faith alone, but this pardon implies no interior renovation of sanctification of the soul. How far the sola-fides doctrine “had no stouter champion before Luther than Pelagius” and whether, in particular, the Protestant conception of fiducial faith dawned upon him many centuries before Luther, probably needs more careful investigation. For the rest, Pelagius would have announced nothing new by this doctrine, since the Antinomists of the early Apostolic Church were already familiar with “justification by faith alone”; on the other hand, Luther’s boast of having been the first to proclaim the doctrine of abiding faith, might well arouse opposition. However, Pelagius insists expressly “Ceterum sine operibus fidei, non legis, mortua est fides”. But the commentary on St. Paul is silent on one chief point of doctrine, i.e. the significance of infant baptism, which supposed that the faithful were even then clearly conscious of the existence of original sin in children.
To explain psychologically Pelagius’s whole line of thought, it does not suffice to go back to the ideal of the wise man, which he fashioned after the ethical principles of the Stoics and upon which his vision was centred. We must also take into account that his intimacy with the Greeks developed in him, though unknown to himself, a one-sidedness, which at first sight appears pardonable. The gravest error into which he and the rest of the Pelagians fell, was that they did not submit to the doctrinal decisions of the Church. While the Latins had emphasized the guilt rather than its punishment, as the chief characteristic of original sin, the Greeks on the other hand (even Chrysostom) laid greater stress on the punishment than on the guilt. Theodore of Mopsuestia went even so far as to deny the possibility of original guilt and consequently the penal character of the death of the body. Besides, at that time, the doctrine of Christian grace was everywhere vague and undefined; even the West was convinced of nothing more than that some sort of assistance was necessary to salvation and was given gratuitously, while the nature of this assistance was but little understood. In the East, moreover, as an offset to widespread fatalism, the moral power and freedom of the will were at times very strongly or even too strongly insisted on assisting grace being spoken of more frequently than preventing grace. It was due to the intervention of St. Augustine and the Church, that greater clearness was gradually reached in the disputed questions and that the first impulse was given towards a more careful development of the dogmas of original sin and grace. >>>>
I have not read Augustine or Pelagius, but to me this sounds like, “Augustine says we don’t have free will, and Pelagius says we do.” I thought that Augustine taught predestination as being compatible with free will. I also thought that Pelagius taught that grace was not necessary for salvation in some cases.