Which theological concept did Pelagius deny?

Pelagius is most notably known for his denial of the concept of Original Sin. He argued that human beings are born without the stain of sin from Adam and Eve and that they have the ability to choose good or evil without the necessity of divine grace. This stance directly opposes the traditional Christian view that Original Sin taints all of humanity and necessitates the need for God's grace for salvation and moral guidance. Consequently, Pelagius believed that individuals could attain righteousness through their own efforts and choices.

Predestination, on the other hand, aligns more with other theological frameworks such as Augustinianism, which asserts that God has predetermined salvation for certain individuals, often reinforced by the inherent concept of Original Sin. Therefore, while Pelagius stressed human autonomy in moral decision-making, it was his denial of Original Sin that fundamentally separated his views from the prevailing Christian doctrines of the early Church.