What Is Pelagianism and Why Is It Condemned as Heresy?

Pelagianism was ardently opposed by Augustine

British monk Pelagius (circa 354 – 420 AD)
British monk and theologian Pelagius (c.360 - c.420), an opponent of the teachings of St Augustine of Hippo, circa 410 CE.

Hulton Archive / Getty Images 

Pelagianism is a set of beliefs associated with the British monk Pelagius (circa AD 354–420), who taught in Rome in the late fourth and early fifth centuries. Pelagius denied the doctrines of original sin, total depravity, and predestination, believing that the human tendency to sin is a free choice. Following this line of reasoning, there is no need for God's intervening grace because people only need to make up their minds to do God’s will. Pelagius’ views were fervently opposed by St. Augustine of Hippo and regarded as heresy by the Christian church.

Key Takeaways: Pelagianism

  • Pelagianism takes its name from the British monk Pelagius, who prompted a school of thought that denied several fundamental Christian doctrines including original sin, the fall of man, salvation by grace, predestination, and the sovereignty of God.
  • Pelagianism was vigorously opposed by St. Augustine of Hippo, a contemporary of Pelagius. It was also condemned as heresy by multiple church councils. 

Who Was Pelagius?

Pelagius was born in the mid-fourth century, most likely in Great Britain. He became a monk but was never ordained. After teaching in Rome for an extended season, he escaped to North Africa around AD 410 amid the threat of Goth invasions. While there, Pelagius became involved in a major theological dispute with Bishop St. Augustine of Hippo on the issues of sin, grace, and salvation. Near the end of his life, Pelagius went to Palestine and then vanished from history.

While Pelagius was living in Rome, he became concerned with the lax morals he observed among the Christians there. He attributed their apathetic attitude toward sin to be a byproduct of Augustine’s teachings that emphasized divine grace. Pelagius was convinced that people had within them the ability to avoid corrupt behavior and choose righteous living even without the help of God’s grace. According to his theology, people are not naturally sinful, but can live holy lives in harmony with God’s will and thereby earn salvation through good works.

Initially, theologians like Jerome and Augustine respected Pelagius’ way of life and objectives. As a devout monk, he had persuaded many affluent Romans to follow his example and relinquish their possessions. But eventually, as Pelagius’ views developed into blatantly unbiblical theology, Augustine took to actively opposing him through preaching and extensive writings.

By AD 417, Pelagius was excommunicated by Pope Innocent I and then condemned as a heretic by the Council of Carthage in AD 418. After his death, Pelagianism continued to expand and was officially condemned again by the Council of Ephesus in AD 431 and once again at Orange in AD 526.

St Augustine
St Augustine, circa 415 AD, Saint Aurelius Augustine of Hippo (354 - 430), Greatest of the Latin Church fathers. Hulton Archive / Getty Images

Pelagianism Definition

Pelagianism rejects several basic Christian doctrines. First and foremost, Pelagianism denies the doctrine of original sin. It rejects the notion that because of Adam’s fall, the entire human race was contaminated by sin, effectively passing sin down to all future generations of humanity.

The doctrine of original sin insists that the root of human sinfulness comes from Adam. Through the fall of Adam and Eve, all people inherited an inclination toward sin (the sinful nature). Pelagius and his immediate followers upheld the belief that Adam’s sin belonged to him alone and did not infect the rest of humanity. Pelagius theorized that if a person’s sin could be attributed to Adam, then he or she would not feel responsible for it and would tend to sin even more. Adam’s transgression, Pelagius supposed, served only as a poor example to his descendants.

Pelagius’ convictions led to the unbiblical teaching that humans are born morally neutral with an equal capacity for either good or evil. According to Pelagianism, there is no such thing as a sinful disposition. Sin and wrongdoing result from separate acts of the human will. 

Pelagius taught that Adam, while not holy, was created inherently good, or at least neutral, with an evenly balanced will to choose between good and evil. Thus, Pelagianism denies the doctrine of grace and the sovereignty of God as they relate to redemption. If the human will has the power and the freedom to choose goodness and holiness on its own, then the grace of God is rendered meaningless. Pelagianism reduces salvation and sanctification to works of human will rather than gifts of God’s grace.

Why Is Pelagianism Considered Heresy?

Pelagianism is considered heresy because it departs from essential biblical truth in several of its teachings. Pelagianism asserts that Adam’s sin affected him alone. The Bible states that when Adam sinned, sin entered the world and brought death and condemnation to everyone, “for everyone sinned” (Romans 5:12-21, NLT).

Pelagianism contends that humans are born neutral towards sin and that there is no such thing as an inherited sin nature. The Bible says people are born into sin (Psalm 51:5; Romans 3:10–18) and considered dead in their transgressions because of disobedience to God (Ephesians 2:1). Scripture affirms the presence of a sinful nature that is at work in humans before salvation:

“The law of Moses was unable to save us because of the weakness of our sinful nature. So God did what the law could not do. He sent his own Son in a body like the bodies we sinners have. And in that body God declared an end to sin’s control over us by giving his Son as a sacrifice for our sins” (Romans 8:3, NLT).

Pelagianism teaches that people can avoid sinning and choose to live righteously, even without the help of God’s grace. This notion gives support to the idea that salvation can be earned through good works. The Bible says otherwise:

You used to live in sin, just like the rest of the world, obeying the devil … All of us used to live that way, following the passionate desires and inclinations of our sinful nature … But God is so rich in mercy, and He loved us so much, that even though we were dead because of our sins, He gave us life when He raised Christ from the dead. (It is only by God’s grace that you have been saved!) … God saved you by his grace when you believed. And you can’t take credit for this; it is a gift from God. Salvation is not a reward for the good things we have done, so none of us can boast about it” (Ephesians 2:2–9, NLT).

What Is Semi-Pelagianism?

A modified form of Pelagius’ ideas is known as Semi-Pelagianism. Semi-Pelagianism takes a middle position between Augustine’s view (with its rock-solid emphasis on predestination and humankind’s total inability to achieve righteousness apart from God’s sovereign grace) and Pelagianism (with its insistence on human will and man’s ability to choose righteousness). Semi-Pelagianism asserts that man maintains a degree of freedom which allows him to cooperate with the grace of God. Man’s will, while weakened and tainted by sin through the Fall, is not totally depraved. In Semi-Pelagianism, salvation is a kind of collaboration between man choosing God and God extending his grace.

The ideas of Pelagianism and Semi-Pelagianism continue to persist in Christianity today. Arminianism, a theology that emerged during the Protestant reformation, tends toward Semi-Pelagianism, although Arminius himself held to the doctrine of total depravity and the need of God’s grace to initiate the human will to turn to God.


  • Dictionary of Theological Terms (p. 324).
  • “Pelagius.” Who’s Who in Christian history (p. 547).
  • Pocket Dictionary of Church History: Over 300 Terms Clearly and Concisely Defined (p. 112).
  • Christian History Magazine-Issue 51: Heresy in the Early Church.
  • Basic Theology: A Popular Systematic Guide to Understanding Biblical Truth (pp. 254–255).
  • “Pelagianism.” The Lexham Bible Dictionary.
  • 131 Christians Everyone Should Know (p. 23). 
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Fairchild, Mary. "What Is Pelagianism and Why Is It Condemned as Heresy?" Learn Religions, Aug. 29, 2020, learnreligions.com/what-is-pelagianism-4783772. Fairchild, Mary. (2020, August 29). What Is Pelagianism and Why Is It Condemned as Heresy? Retrieved from https://www.learnreligions.com/what-is-pelagianism-4783772 Fairchild, Mary. "What Is Pelagianism and Why Is It Condemned as Heresy?" Learn Religions. https://www.learnreligions.com/what-is-pelagianism-4783772 (accessed June 9, 2023).