other · 405 · Rome
Pelagius was a British ascetic of formidable seriousness who came to Rome about 380 and was appalled by the moral slackness of Christians in a capital that had become nominally Christian. What he heard read out — give what you command, and command what you will, from the Confessions — struck him as an excuse: if a man cannot obey without a gift he has not been given, then commands are a mockery and no one is responsible. So he answered that God does not command the impossible, that the will is genuinely free, and that grace is the assistance of law, example and forgiveness rather than an interior necessity. Augustine took the opposite position further with every year of the fight, until he was arguing that the will is not merely wounded but bound, that grace is irresistible where it is given, and that who receives it is settled beforehand. The quarrel produced both the doctrine of original sin in its western form and every argument about predestination the west has had since. It is also a rare case where this dataset can be exact about the trigger, because both sides record it.
What set it off?
A single sentence of Augustine's, read aloud, that Pelagius could not bear.