Sixtus III’s main claim to fame (earning him a day in the Calendar) is his success at suppressing a heresy known as Pelagianism–one of the most dangerous-to-the-Church heresies ever.

Pelagianism (named for Pelagius) taught that humans were not by nature bad, nor in any way prone to evil. He did not believe in the doctrine of original sin, and did believe that humans are endowed with the ability to choose good or to choose evil. At worst, Pelagius taught that humans were morally neutral. Pelagius took seriously the idea that humans were created in God’s image, and that we are even capable of leading sinless lives, assisted in doing good by the grace of God (much the way a flame is assisted by oxygen).

It’s easy to say “Whether or not humans are born with original sin, we all still sin so we all need forgiveness—so what’s the big deal about this particular heresy?” Here’s how it matters: If you say that humans are not by nature prone to sin, then the church is no longer necessary. The church is displaced from being essential for providing guidance, even deliverance, to each and every hopelessly sinful human being. Rather, human beings are in the position of deciding whether a congregation or even the capital-C Church is helpful to them in living out the good and faithful lives that they seek.

This point cannot be overstated: Pelagianism makes the Church dependent on human judgment, not human judgment dependent on the Church. Pelagianism requires the Church to demonstrate that it can amplify the aspirations and dreams of  people who want to lead good, creative lives, rather than persons being required to demonstrate their worthiness to partake of the Church’s salvation by admitting their worthlessness and utter dependence upon the Church to overcome their sinful nature.

It’s easy to understand why those who were among the most successful at suppressing the Pelagians (like our Sixtus III here) became heroes to the Institution. But that doesn’t make them right (let alone helpful)!