Heresies Through Church History what the church has had to name, and why it had to name them
A historically careful survey of the ten major heresies the church has had to identify and answer, from Gnosticism in the second century to the prosperity gospel in our own. For each: the historical context, the core error, the biblical and doctrinal response, and why it still matters today. A Reformed evangelical orientation that uses the word "heresy" carefully — not as a club to swing at every disagreement, but as a technical term for the teachings that strike at the gospel itself.
HOW TO READ THIS PAGE — The page is in three parts. First, a framework callout explains what "heresy" means and does not mean in classical Christian usage — the New Testament term hairesis, the development of the technical vocabulary, the distinction between gospel-denying heresy and lesser kinds of doctrinal disagreement. Second, a four-card panel distinguishes heresy, error, immaturity, and secondary disagreement — four kinds of doctrinal trouble that Christians sometimes lump together to everyone's harm. Third, the ten major heresies themselves, in chronological order, each in a card giving the historical context, the core error, the biblical response, and a "why it matters today" pull-out.
For the surrounding pillar — the eras these heresies arose in, the councils that addressed them, the creeds and confessions that confessed the orthodox response — see the Church History hub, the Eras of Church History survey, the Ecumenical Councils survey, and the Creeds and Confessions survey.
The Greek word is hairesis. In its earliest New Testament uses (Acts 5:17; 15:5; 26:5) it simply means a "school" or "party" — the sect of the Sadducees, the sect of the Pharisees. It is morally neutral. But Paul already uses the word more negatively in 1 Corinthians 11:19 and Galatians 5:20 (where haireseis is listed among the works of the flesh), and 2 Peter 2:1 speaks decisively of "destructive heresies" introduced by false teachers who deny the Master who bought them. By the time of the early fathers (Ignatius, Irenaeus) the word has narrowed to its classical technical sense: a teaching that denies a doctrine the church has identified as essential to the gospel.
Heresy is a technical term, not a slur. To call a teaching "heresy" in the classical sense is not to call its teachers wicked or stupid. It is to make a precise theological claim: this teaching, if held consistently and acted upon, cuts the holder off from the gospel of Jesus Christ. Arius was not a bad man. Pelagius was not a bad man. Nestorius was probably a faithful pastor by his own lights. But their teachings, if followed, would have lost the church the gospel — and that is what made them heresies and not lesser errors.
Heresy assumes a Christian context. A Hindu, a Muslim, or an atheist is not a heretic — those are followers of other religions or none. Heresy is the deviation of a baptised Christian (or a Christian movement) from the Christian rule of faith. This is why the church has always taken heresy with particular seriousness: it cloaks itself in Christian vocabulary, claims the Christian Scriptures, and uses Christian channels of transmission — and so endangers the church in a way external religions do not.
To call something heresy is therefore to make four claims at once: (1) the teaching falsifies what Scripture teaches; (2) it does so on a matter the church has identified as essential to the gospel; (3) those who hold it consistently are outside the apostolic faith they claim; and (4) the church must therefore name and answer it — pastorally where possible, formally when necessary. The ten teachings surveyed below meet all four tests.
Four kinds of doctrinal trouble
Heresy
A teaching that denies a doctrine essential to the gospel: the deity of Christ, the Trinity, the bodily resurrection, justification by faith, the authority of Scripture, the atoning death of Christ. Those who hold heresy consistently are outside the gospel itself. The church names heresy formally and refuses fellowship to those who promote it. The ten teachings on this page are heresies in this technical sense.
Error
A mistaken view on a doctrine that is not core to the gospel. Wrong but not damning. Examples: a defective view of the sacraments, an over-realised eschatology, a wrong reading of a particular passage. Errors are to be corrected through patient teaching and Scripture; the people who hold them remain brothers and sisters in Christ. Reformed and Lutheran Christians regard each other's distinctive errors this way, not as heresies.
Immaturity
The incomplete or confused thinking of a believer who is still being formed. A new convert holds many things wrongly because she has not yet been taught them rightly; an older believer can be immature on doctrines outside his everyday experience. Immaturity is to be met with catechesis, not anathema. Most apparent "errors" in young Christians are actually immaturity and resolve under teaching.
Secondary disagreement
Christians who agree on the essentials but differ on important non-essentials. Mode and subjects of baptism, form of church government, end-times schemes, regulative versus normative principle of worship, role of women in the church, age of the earth. These matter — sometimes they require separate denominations — but they do not unchurch the disagreeing party. To treat them as heresies is to cheapen the word and to fracture the body of Christ.
Gnosticism 2nd century · multiple schools across the eastern Mediterranean · the church's first sustained doctrinal struggle
Irenaeus's Against Heresies (c. 180) is the great patristic refutation. The orthodox response insisted on four interconnected truths the Gnostics denied: (1) the one God is both Creator and Redeemer — the God of Israel is the Father of Jesus Christ; (2) creation is good (Gen 1:31), and matter is not evil; (3) the incarnation is real — the Word became flesh (John 1:14), not the appearance of flesh; (4) the resurrection is bodily — Christ was raised in his real body and Christians will be raised in their real bodies. The early creeds (especially the Apostles' Creed) crystallised these convictions in their opening articles: "I believe in God the Father almighty, maker of heaven and earth… born of the Virgin Mary… the resurrection of the body."
Focused page: Gnosticism
Marcionism c. 144 onward · Rome and across the empire · Marcion of Sinope, excommunicated 144
Tertullian's Against Marcion (in five books, c. 207) is the major early refutation. The orthodox response insisted that the God of Israel and the God of Jesus Christ are one and the same: the Father whom Jesus called "my Father" is the God who created the world, gave the law, and spoke through the prophets. The Old Testament is Christian Scripture; the church inherits it from the apostles, who themselves received it from their Lord (Luke 24:27, 44; 2 Tim 3:15–17). Marcion's heresy actually prompted the church to think more deliberately about its canon — not because the church needed Marcion to tell it what was Scripture, but because Marcion's truncated canon required a clear public response.
Focused page: Marcionism
Arianism c. 318 onward · Alexandria and the wider eastern church · Arius (c. 256–336), condemned at Nicaea 325
Athanasius of Alexandria is the great hero of the anti-Arian controversy — exiled five times for refusing to compromise the Nicene confession. His Orations Against the Arians and On the Incarnation are the classic Nicene defences. The orthodox response insisted that the Son is fully God in the same sense that the Father is God, sharing one and the same divine substance (homoousios), and that this is no philosophical innovation but the plain teaching of the New Testament: John 1:1, John 8:58, John 10:30, John 17:5, Philippians 2:6, Colossians 1:15–20, Colossians 2:9, Hebrews 1:3, 8, 10–12, and many more. See the Ecumenical Councils survey on Nicaea I and Constantinople I.
Focused page: Arianism
Apollinarianism c. 360–381 · Laodicea · Apollinaris of Laodicea (c. 310–c. 390), condemned at Constantinople I (381)
Gregory of Nazianzus's first letter to Cledonius (c. 382) gives the classic refutation in the phrase that became axiomatic: "what is not assumed is not healed; but what is united to God is also being saved." If Christ did not assume a complete human nature — body and rational soul together — then no complete human nature has been redeemed. Apollinaris's intentions were Christological; his result was soteriological catastrophe. The orthodox response, leading directly into the work of Ephesus (431) and Chalcedon (451), insisted on a complete human nature in Christ: body, soul, and rational mind.
Focused page: Apollinarianism
Nestorianism 428–431 · Constantinople and Ephesus · Nestorius (c. 386–c. 450), condemned at Ephesus (431)
Cyril of Alexandria's twelve anathemas and his letters to Nestorius gave the orthodox response: Christ is one person (hypostasis) in two natures. The same one Christ who was born of Mary is the eternal Son of God; Mary therefore bore "God in the flesh." Theotokos is not a Marian title in disguise but a Christological one — it claims that the one she bore is truly God. The Reformed receive this against Nestorius without reservation: Mary as theotokos in the strict sense means Christ is one Subject who is fully God and fully man.
Focused page: Nestorianism
Eutychianism and Monophysitism 448–451 · Constantinople and Chalcedon · Eutyches (c. 378–454), condemned at Chalcedon (451)
Leo's Tome and the Chalcedonian Definition gave the orthodox response. The Definition's famous "four negatives" — without confusion, without change, without division, without separation — close off Eutyches's error (the first two) along with Nestorius's (the second two). Christ is one person in two natures; the natures are not mixed; the human is not absorbed into the divine; Christ remains fully human (of the same substance as us in his humanity) as well as fully divine. See the Ecumenical Councils survey on Chalcedon.
Focused page: Eutychianism / Monophysitism
Pelagianism c. 410–431 · Rome, North Africa, Palestine · Pelagius (c. 354–c. 420), condemned by African synods (411, 418) and reaffirmed at Ephesus (431)
Augustine's response is the foundational text of Western soteriology and the seedbed of the Reformation a millennium later. Against Pelagius he insisted on original sin (the whole human race is fallen in Adam), on the total depravity of the will (the unregenerate cannot of themselves turn to God), on the necessity and effectiveness of inward grace (the Spirit must regenerate the dead heart), and on God's gracious election (those who come to Christ do so because the Father gave them to the Son before the foundation of the world). Semi-Pelagianism — the milder view that the will initiates and grace assists — was condemned at the Second Council of Orange (529).
Focused page: Pelagianism
Socinianism 16th–17th century · Poland, Transylvania, and (later) Holland and England · Lelio (1525–1562) and Faustus Socinus (1539–1604)
The Socinians read the Bible with a sharp rationalist hermeneutic: whatever does not square with their definition of what is reasonable must be reinterpreted. The Reformed orthodox of the seventeenth century — Francis Turretin in Geneva, John Owen in England, the Westminster divines — gave sustained responses. Owen's Vindiciae Evangelicae (1655) is a particularly thorough refutation. The Westminster Confession's careful articulations on the Trinity (2.3), on Christ the Mediator (8), and on Christ's satisfaction (8.4–5) and justification (11) are written, in part, against Socinian denials.
Focused page: Socinianism
Theological Liberalism 19th–20th century · Germany, Britain, the United States · Friedrich Schleiermacher (1768–1834) to Adolf von Harnack (1851–1930) and beyond
The classic Reformed response is J. Gresham Machen's Christianity and Liberalism (1923). Machen's argument is not that liberals are bad people but that liberalism, taken seriously, is not a variant of Christianity at all: it is a different religion using Christian vocabulary. Where Christianity confesses a supernatural God who has acted in history through real miracles, a real incarnation, a real atonement, and a real bodily resurrection, liberalism denies all of these. The two are not different denominations within the same religion; they are different religions. The Reformed Princeton tradition — Charles Hodge, A. A. Hodge, Warfield, Machen — built up the great twentieth-century evangelical defence against liberalism.
Focused page: Theological Liberalism
Word of Faith and Prosperity Theology mid-20th century to the present · Tulsa, then globally · E. W. Kenyon (1867–1948), Kenneth Hagin (1917–2003), Kenneth Copeland, and numerous successors
Reformed and broader evangelical critics — D. A. Carson, John MacArthur, Hank Hanegraaff (Christianity in Crisis), Costi Hinn, Conrad Mbewe and other African Reformed voices — have given thorough refutations. The biblical and doctrinal critique runs along several converging lines. (1) Christ's atonement secures forgiveness of sin and reconciliation with God, not the believer's earthly health and wealth; the apostles themselves lived in poverty, suffering, and martyrdom. (2) The "little gods" teaching is a denial of the Creator–creature distinction that the Scriptures everywhere assume. (3) "Positive confession" is closer to ancient magical religion than to biblical faith. (4) The fruit of the prosperity gospel — the impoverishment of the poor by promises of wealth-by-seed, the inoculation of the genuinely suffering against the comfort of the cross — is bad fruit by any test (Matt 7:15–20).
Focused page: Word of Faith and Prosperity Theology
Conclusion: heresies as teachers in reverse
Ten heresies across nineteen centuries. Each was named for a reason. Each tested the church on a doctrine the church had already received from the apostles but had not yet had to defend with precision. Each, once named and answered, became a permanent boundary marker — a reminder of what Christian confession may not give up without ceasing to be Christian.
For the believer who wants to use this page well, three suggestions. First, learn the historical heresies as types. Once you have grasped what Arius actually taught, you will recognise his theology under any modern packaging. Once you have read Augustine on Pelagius, you will see Pelagian shapes in many evangelical sermons. The fathers' diagnoses still work because human nature has not changed and the temptations of theology have not changed.
Second, use the word "heresy" carefully. Christians who scatter the word at every disagreement do real damage — to the body, to the watching world, and to their own credibility when a real heresy actually arises. Most disagreements between believing Reformed and Lutheran Christians, between Presbyterians and Baptists, between credo- and paedobaptists, between premillennial and amillennial readers of Revelation, are not heresies. They are secondary disagreements — sometimes important, often church-dividing, but not gospel-denying.
Third, remember that heresies are teachers in reverse. The church learned the deity of Christ in sharper relief because of Arius. It learned the Trinity in sharper relief because of the Pneumatomachi. It learned the two natures of Christ in sharper relief because of Eutyches and Nestorius together. It learned salvation by grace in sharper relief because of Pelagius. Even the modern liberal and prosperity heresies serve, by way of contrast, to clarify what the gospel actually is and is not. The good news is bigger and clearer in the light of what it has had to repudiate.