What a great day this was 1600 years ago, when a heretic, Pelagius, the likes of whom are still around today, was booted out of the fellowship. What did he teach?
One of the false doctrines (and there were many) this influential Irish monk taught was that there was no original sin. Adam’s sin, according to Pelagius, was his alone, and he would pay the consequences himself—alone. His children were innocent and could choose to sin or not to. They were not totally depraved but could choose to be obedient. In other words, humanity was born without sin and were free to obey or not obey God’s commandments.
Augustine of Hippo tried to set him straight to no avail. His argument, the correct one, is that all have sinned and fall short of God’s glory and that victory from sin is impossible apart from the saving grace and forgiveness provided by Jesus Christ.
Two church councils, one from North Africa and another in Mileve requested that Pope Innocent I excommunicate Pelagius. He was on January 27, 417. A year later, another council affirmed the decision. Get a fuller understanding of this false doctrine here.