Pelagianism is the belief that original sin did not taint human nature and that mortal will is still capable of choosing good or evil without special Divine aid. The teachings of Pelagius are generally associated with the rejection of original sin and the rejection of infant baptism. Although the writings of Pelagius are not longer extant, the eight canons of the Catholic Council of Carthage provided corrections to the perceived errors of the early Pelagianists:
- Death did not come to Adam from a physical necessity, but through sin.
- New-born children must be baptized on account of original sin.
- Justifying grace not only avails for the forgiveness of past sins, but also gives assistance for the avoidance of future sins.
- The grace of Christ not only discloses the knowledge of God's commandments, but also imparts strength to will and execute them.
- Without God's grace it is not merely more difficult, but absolutely impossible to perform good works.
- Not out of humility, but in truth must we confess ourselves to be sinners.
- The saints refer the petition of the Our Father, "Forgive us our trespasses", not only to others, but also to themselves.
- The saints pronounce the same supplication not from mere humility, but from truthfulness.
Some codices containing a ninth canon (Denzinger, loc. cit., note 3): Children dying without baptism do not go to a "middle place" (medius locus), since the non reception of baptism excludes both from the "kingdom of heaven" and from "eternal life".
This theological theory is named after Pelagius (AD 354 – AD 420/440), although he denied, at least at some point in his life, many of the doctrines associated with his name.
Pelagianism stands in contrast to the theological system of the Catholic Church known as Augustinianism. Semi-Pelagianism is a modified form of Pelagianism again condemned by the Catholic Church at the Second Council of Orange in AD 529.
Pelagius was opposed by Augustine, and rejected the Augustinian concept of grace. When Pelagius taught that moral perfection was attainable in this life without the assistance of divine grace through human free will, Augustine contradicted this by saying that perfection was impossible without grace because we are born sinners with a sinful heart and will. The Pelagians charged Augustine on the grounds that the doctrine of original sin amounted to Manichaeism: the Manichaeans taught that the flesh was in itself sinful (and they denied that Jesus came in the flesh) – and this charge would have carried added weight since contemporaries knew that Augustine himself had been a Manichaean layman before his conversion to Christianity. Augustine also taught that a person's salvation comes solely through an irresistible free gift, the efficacious grace of God, but that this was a gift that one had a free choice to accept or refuse.
Pelagianism was attacked in 415 at the Council of Diospolis (also known as Lydda; modern Lod) and condemned in 418 at the Council of Carthage. These condemnations were ratified at the Council of Ephesus in 431. The strict moral teachings of the Pelagians were influential in southern Italy and Sicily, where they were openly preached until the death of Julian of Eclanum in 455, and in Britain until the coming of Saint Germanus of Auxerre c 429.
Little or nothing is known about the life of Pelagius. Although he is frequently referred to as a British monk, it is by no means certain where his origins lay. Augustine says that he lived in Rome "for a very long time" and referred to him as "Brito" to distinguish him from a different man called Pelagius of Tarentum. Bede refers to him as "Pelagius Bretto". St. Jerome suggests he was of Scottish descent but in such terms as to leave it uncertain as to whether Pelagius was from Scotland or Ireland. Other sources place his origins in Brittany.  He was certainly well known in the Roman province, both for the harsh asceticism of his public life, as well as the power and persuasiveness of his speech. Until his more radical ideas saw daylight, even such pillars of the Church as Augustine referred to him as “saintly.”
Pelagius taught that the human will, as created with its abilities by God, was sufficient to live a sinless life, although he believed that God's grace assisted every good work. Pelagius, taking what is still the standard Orthodox view, did not believe that all humanity was guilty in Adam's sin, but said that Adam had condemned humankind through bad example, and that Christ’s good example offered humanity a path to salvation, through sacrifice and through instruction of the will. Jerome emerged as one of the chief critics of Pelagianism, because, according to him, sin was an unavoidable part of human nature.
Comparison of teaching
Church Fathers on free will
Many of the Church Fathers taught that humans have the power of free will and the choice over good and evil. Justin Martyr said that 'every created being is so constituted as to be capable of vice and virtue. For he can do nothing praiseworthy, if he had not the power of turning either way'. 'Unless we suppose man has the power to choose the good and refuse the evil, no one can be accountable for any action whatever.' (The First Apology, 43). Tertullian also argued that no reward can be justly bestowed, no punishment can be justly inflicted, upon him who is good or bad by necessity, and not by his own choice. (Doctrine of the Will by Asa Mahan, p. 61). Likewise Origen, and Clement of Alexandria
Justin Martyr said, “Let some suppose, from what has been said by us, that we say that whatever occurs happens by a fatal necessity, because it is foretold as known beforehand, this too we explain. We have learned from the prophets, and we hold it to be true, that punishments, chastisements, and good rewards, are rendered according to the merit of each man’s actions. Now, if this is not so, but all things happen by fate, then neither is anything at all in our own power. For if it is predetermined that this man will be good, and this other man will be evil, neither is the first one meritorious nor the latter man to be blamed. And again, unless the human race has the power of avoiding evil and choosing good by free choice, they are not accountable for their actions.”
Justin Martyr also said, “I have proven in what has been said that those who were foreknown to be unrighteous, whether men or angels, are not made wicked by God’s fault. Rather, each man is what he will appear to be through his own fault.”
Tatian said, “We were not created to die. Rather, we die by our own fault. Our free will has destroyed us. We who were free have become slaves. We have been sold through sin. Nothing evil has been created by God. We ourselves have manifested wickedness. But we, who have manifested it, are able again to reject it.”
Theophilus said, “If, on the other hand, he would turn to the things of death, disobeying God, he would himself be the cause of death to himself. For God made man free, and with power of himself.”
Irenaeus said, “But man, being endowed with reason, and in this respect similar to God, having been made free in his will, and with power over himself, is himself his own cause that sometimes he becomes wheat, and sometimes chaff.”
Irenaeus also said, “Let your light so shine before men, that they may see your good deeds’…And ‘Why call me, Lord, Lord, and do not do the things that I say?’…All such passages demonstrate the independent will of man…For it is in man’s power to disobey God and to forfeit what is good.”
Tertullian said, “I find, then, that man was constituted free by God. He was master of his own will and power…For a law would not be imposed upon one who did not have it in his power to render that obedience which is due to law. Nor again, would the penalty of death be threatened against sin, if a contempt of the law were impossible to man in the liberty of his will…Man is free, with a will either for obedience or resistance.
Regarding this issue, Pelagius taught:
“Whenever I have to speak on the subject of moral instruction and conduct of a holy life, it is my practice first to demonstrate the power and quality of human nature and to show what it is capable of achieving, and then to go on to encourage the mind of my listener to consider the idea of different kinds of virtues, in case it may be of little or no profit to him to be summoned to pursue ends which he has perhaps assumed hitherto to be beyond his reach; for we can never end upon the path of virtue unless we have hope as our guide and compassion…any good of which human nature is capable has to be revealed, since what is shown to be practicable must be put into practice."
"It was because God wished to bestow on the rational creature the gift of doing good of his own free will and the capacity to exercise free choice, by implanting in man the possibility of choosing either alternative...he could do either quite naturally and then bend his will in the other direction too. He could not claim to possess the good of his own volition, unless he was the kind of creature that could also have possessed evil. Our most excellent creator wished us to be able to do either but actually to do only one, that is, good, which he also commanded, giving us the capacity to do evil only so that we might do His will by exercising our own. That being so, this very capacity to do evil is also good - good, I say, because it makes the good part better by making it voluntary and independent, not bound by necessity but free to decide for itself."
"Those who are unwilling to correct their own way of life appear to want to correct nature itself instead."
"And lest, on the other hand, it should be thought to be nature's fault that some have been unrighteous, I shall use the evidence of the scripture, which everywhere lay upon sinners the heavy weight of the charge of having used their own will and do not excuse them for having acted only under constraint of nature."
"Yet we do not defend the good of nature to such an extent that we claim that it cannot do evil, since we undoubtedly declare also that it is capable of good and evil; we merely try to protect it from an unjust charge, so that we may not seem to be forced to do evil through a fault of our nature, when, in fact, we do neither good nor evil without the exercise of our will and always have the freedom to do one of the two, being always able to do either."
"Nothing impossible has been commanded by the God of justice and majesty...Why do we indulge in pointless evasions, advancing the frailty of our own nature as an objection to the one who commands us? No one knows better the true measure of our strength than he who has given it to us nor does anyone understand better how much we are able to do than he who has given us this very capacity of ours to be able; nor has he who is just wished to command anything impossible or he who is good intended to condemn a man for doing what he could not avoid doing."
"Grace indeed freely discharges sins, but with the consent and choice of the believer."
"Obedience results from a decision of the mind, not the substance of the body."
An unknown Pelagian taught:
"Is it possible then for a man not to sin? Such a claim is indeed a hard one and a bitter pill for sinners to swallow; it pains the ears of all who desire to live unrighteous. Who will find it easy now to fulfil the demands of righteousness, when there are some who find it hard even to listen to them?"
"When will a man guilty of any crime or sin accept with a tranquil mind that his wickedness is a product of his own will, not of necessity, and allow what he now strives to attribute to nature to be ascribed to his own free choice? It affords endless comfort to transgressors of the divine law if they are able to believe that their failure to do something is due to inability rather than disinclination, since they understand from their natural wisdom that no one can be judged for failing to do the impossible and that what is justifiable on grounds of impossibility is either a small sin or none at all."
"Under the plea that it is impossible not to sin, they are given a false sense of security in sinning...Anyone who hears that it is not possible for him to be without sin will not even try to be what he judges to be impossible, and the man who does not try to be without sin must perforce sin all the time, and all the more boldly because he enjoys the false security of believing that it is impossible for him not to sin...But if he were to hear that he is able not to sin, then he would have exerted himself to fulfil what he now knows to be possible when he is striving to fulfil it, to achieve his purpose for the most part, even if not entirely."
"Consider first whether that which is such that a man cannot be without it ought to be described as sin at all; for everything which cannot be avoided is now put down to nature but it is impious to say that sin is inherent in nature, because in this way the author of nature is being judged at fault… how can it be proper to call sin by that name if, like other natural things, it cannot be avoided, since all sin is to be attributed to the free choice of the will, not to the defects of nature?"
How to react to Pelagius has remained a question in Christian theology. Thomas Bradwardine (c. 1290-1349) wrote De causa Dei contra Pelagium et de virtute causarum ad suos Mertonenses. Johann Pupper, also known as Johannes von Goch (c. 1400-1475), an Augustinian, recommended a return to the text of the Bible as a remedy for Pelagianism.
Later writers, such as Martin Luther (1483-1546), John Calvin (1509-1564), and Cornelius Jansen (1585-1638) reacted in different ways against Pelagianism, and evaluations of Lutheran, Reformed, and Jansenist theologies have often turned on the question of what is or is not Pelagian.
Mormonism (The Church of Jesus Christ of Latter-day Saints)
Unconventional Mormon theologian Sterling M. McMurrin has argued that “[t]he theology of Mormonism is completely Pelagian.” Mormon theology teaches that the Atonement of Jesus Christ has overcome the effects of "original sin" for all mankind. For example, the Book of Mormon, a text sacred to the Church of Jesus Christ of Latter Day Saints, teaches:
[T]he Messiah cometh in the fullness of time, that he might redeem the children of men from the fall. And because they are redeemed from the fall they have become free forever, knowing good and evil, to act for themselves and not to be acted upon, save it be by the punishment of the law at that great and last day, according to the commandments which God has given. 
- Meister Eckhart
- Fall of Man
- Charles Grandison Finney
- Mormon cosmology
- The Church of Jesus Christ of Latter-day Saints
- J., Pohle. "Pelagius and Pelagianism". Catholic Encyclopedia.
- (Denzinger, "Enchir.", 10th ed., 1908, 101-8.
- González, Justo (2005), "Pelagianism", Essential Theological Terms, Westminster John Knox Press, p. 128, ISBN 978-0-664-22810-1, retrieved 4 April 2013
- The Cambridge Companion to Augustine. 2001. , eds. Eleonore Stump, Norman Kretzmann. New York: Cambridge University Press. 130-135.
- *Transcript From The Council of Diospolis (Lydda) Against Pelagius, 415AD
- Dictionary of Philosophy and Religion by William L Reese, Humanities Press 1980 p.421
- controverscial.com Unitarian Universalism
- Bede's Ecclesiastical History of the English People: A Historical Commentary
- The Oxford Handbook of Early Christian Studies
- said, “The soul does not incline to either part out of necessity, for then neither vice nor virtue could be ascribed to it; nor would its choice of virtue deserve reward; nor its declination to vice punishment.”(The Works of the Reverend John Fletcher p.212) Again, “How could God require that of man which he [man] had not power to offer Him?” (Doctrine of the Will by Asa Mahan, p. 62, published by Truth in Heart)
- “Neither promises nor apprehensions, rewards, no punishments are just if the soul has not the power of choosing and abstaining; if evil is involuntary.” (Doctrine of the Will by Asa Mahan, p. 63, published by Truth in Heart)
- Dialogue with Trypho, chapter 95
- Dialogue with Trypho, chapter 140
- Address to the Greeks, 11
- c.170, A Dictionary of Early Christian Beliefs by David Bercot, p. 286, published by Hendrickson Publishers
- c.180, A Dictionary of Early Christian Beliefs by David Bercot, p. 286, published by Hendrickson Publishers
- c.180, A Dictionary of Early Christian Beliefs by David Bercot, p. 287, published by Hendrickson Publishers
- c.195, A Dictionary of Early Christian Beliefs by David Bercot, p. 287, published by Hendrickson Publishers
- "It is not incomplete size of stature, nor a definite measure of time, nor additional secret teachings in things that are manly and more perfect, that the apostle, who himself professes to be a preacher of childishness, alludes to when he sends it, as it were, into banishment; but he applies the name “children” to those who are under the law, who are terrified by fear as children are by bugbears; and “men” to us who are obedient to the Word and masters of ourselves, who have believed, and are saved by voluntary choice, and are rationally, not irrationally, frightened by terror." Clement of Alexandria. (1885). The Instructor. In A. Roberts, J. Donaldson, & A. C. Coxe (Eds.), The Ante-Nicene Fathers: Fathers of the Second Century: Hermas, Tatian, Athenagoras, Theophilus, and Clement of Alexandria (Entire) (Vol. 2, p. 217). Buffalo, NY: Christian Literature Company.
- c.207, A Dictionary of Early Christian Beliefs by David Bercot, p. 288, published by Hendrickson Publishers
- The Letters of Pelagius and his Followers by B. R. Rees, pg 36-37, published by The Boydell Press
- The Letters of Pelagius and his Followers by B. R. Rees, pg 38, published by The Boydell Press
- The Letters of Pelagius and his Followers by B. R. Rees, pg 39, published by The Boydell Press
- The Letters of Pelagius and his Followers by B. R. Rees, pg 43, published by The Boydell Press
- The Letters of Pelagius and his Followers by B. R. Rees, pg 53-54, published by The Boydell Press
- The Letters of Pelagius and his Followers by B. R. Rees, pg 92, published by The Boydell Press
- The Letters of Pelagius and his Followers by B. R. Rees, pg 90, published by The Boydell Press
- The Letters of Pelagius and his Followers by B. R. Rees, pg 167, published by The Boydell Press
- The Letters of Pelagius and his Followers by B. R. Rees, pg 167-168, published by The Boydell Press
- The Letters of Pelagius and his Followers by B. R. Rees, pg 168, published by The Boydell Press
- The Letters of Pelagius and his Followers by B. R. Rees, pg 168-169, published by The Boydell Press
- Heiko Oberman (1957), Archbishop Thomas Bradwardine, a Fourteenth Century Augustinian: A Study of His Theology in Its Historical Context, Utrecht: Gemink & Zoon.
- "Johannes von Goch", in Webster's Biographical Dictionary (1960), Springfield, MA: Merriam-Webster.
- Bernard Cottret, Monique Cottret, and Marie-José Michel, edd. (2002), Jansénisme et puritanisme: Actes du colloque du 15 septembre 2001, tenu au Musée National des Granges des Port-Royal-des-Champs, Paris: Nolin.
- McMurrin, Sterling M. The Theological Foundations of the Mormon Religion 1965
- 2 Nephi 2:27-28, The Book of Mormon
- Writings by Pelagius
- Letters of Pelagius: To A Presbyter, Augustine of Hippo, and Pope Innocent I
- Confession of Faith
- On Nature
- Defense Of The Freedom Of The Will
- Expositions on Paul’s Epistle
- Epistle to Demetrias[dead link]
- Excerpts Out Of Divine Scriptures: Book One (a.k.a. Chapters)
- Written Anathema
- The Writings of the legendary Pelagians
- Canons From The Council Of Carthage Against Pelagianism, May 1, 418
- Catholic Encyclopedia: Pelagius and Pelagianism
- Pelagians, Donatists, Monks, Anabaptists and other Perfectionists - a sympathetic look at Pelagianism and similar 'perfectionist' movements
- Pelagius Library: Online site dedicated to the study of Pelagius
- Pelagianism: The Religion of Natural Man - a critical look at Pelagianism