The year is not settled. Astronomical and calendar arguments put it at either AD 30 or AD 33, and serious scholars hold both. What the earliest Christians agreed on was not a date. It was a claim. Jesus of Nazareth was executed under Pontius Pilate, and was raised. Paul, writing about twenty years later, quotes a summary that was already fixed and handed on before he got to it.

Kerygma · Resurrection

Acts 2 puts the birth of the church at a Jewish harvest festival. The Spirit is given, and Peter preaches a sermon that reads the whole Old Testament as pointing forward. That pattern holds for centuries. Christian preaching starts in the Hebrew scriptures and argues from them. The date follows the crucifixion date, so it is no more settled than that one is.

Ekklesia · Pneumatology

A Pharisee busy suppressing the new movement is stopped on the road to Damascus. Nearly a third of the New Testament is attributed to him. His letters are also the oldest Christian documents we have, written before any of the gospels reached their final shape.

Justification · Paul

Acts 15 records the first big argument and the first decision taken by a gathering. The question was whether Gentile converts had to be circumcised and keep the law of Moses. The answer was no. That made Christianity a universal movement rather than a sect inside Judaism, and it set the habit of settling disputes by getting everyone into one room.

Council · Law and gospel

Paul wrote to particular churches about particular problems. He was not composing a systematic theology and he had no idea he was writing a Bible. That it became scripture anyway is one of the odder facts about the New Testament. It is also why reading him well means asking first what situation he was answering.

Tacitus, no friend of the Christians, records that Nero pinned the blame for the fire on a group already hated for their supposed crimes. Tradition puts the deaths of both Peter and Paul in Rome around this time. This is persecution as local scapegoating rather than imperial policy, which is how most of it worked for the next two centuries.

Martyrdom

Titus takes Jerusalem and burns the Temple. Sacrifice stops. Judaism reforms around the synagogue and the text. Christianity, which had already started calling Jesus the true temple and the final sacrifice, is pushed further from its parent. A great deal of New Testament scholarship turns on whether a given document was written before this date or after it.

Supersessionism · Temple and sacred geography

The dates are contested and the range above is wide on purpose. What matters theologically is a decision the church made later and could have made otherwise. Faced with four accounts that do not always agree on the detail, it refused to blend them into one. Tatian tried that, in the Diatessaron, and nobody followed him.

Canon · The fourfold gospel

The church at Corinth had thrown out its leaders. The church at Rome wrote to tell them to put them back. It is a window into how the earliest congregations settled a row, and later writers quote it as though it carried weight. Whether it shows an early Roman primacy or just one large church advising another is still argued.

The Apostolic Fathers · Clement of Rome · Episcopacy

The Teaching of the Twelve Apostles covers baptism, fasting, the eucharist, and how to tell a real travelling prophet from a freeloader. Estimates run from the 50s to the early second century, which is a very large margin. The plainness is the attraction. This is what an ordinary congregation was actually told to do.

The Apostolic Fathers · Views of the eucharist

Ignatius wrote to churches along the road to Rome, begging them not to step in and save him. The letters press two things hard. The reality of Christ's flesh, against people who said he only seemed human. And unity around the bishop. He is the first writer we have who uses the phrase catholic church.

Docetism · Episcopacy · Ignatius of Antioch

Pliny, governor of Bithynia, asks the emperor what to do with Christians and describes what he has learned under interrogation. They meet before dawn, sing to Christ as to a god, and swear an oath not to commit crimes. It is one of the very few descriptions of early Christian practice by someone with no interest in making it look good.

Marcion taught that the God of the Hebrew scriptures was a lesser and harsher being than the Father of Jesus. He made his own shortened canon, an edited Luke and ten letters of Paul. The reaction against him pushed the wider church to say out loud which books it did receive, and to insist that the God of Israel and the Father of Jesus are the same God.

Canon · Marcionism

Justin was a working philosopher before he converted and he kept the trade afterwards. His case is that whatever is true in Greek philosophy already belongs to Christ, the Word who scatters seeds of truth everywhere. The Apology also holds the earliest full description of a Sunday service that we have.

Apologist · Justin Martyr · Logos

Polycarp of Smyrna is said to have been taught by John. The account of his death is usually taken as the earliest surviving martyr act, though some argue parts of it were added later. It shapes his death deliberately to echo the passion of Jesus. The date is disputed by about a decade. His answer to the proconsul, that he has served Christ eighty six years and Christ has done him no wrong, is one of the most quoted lines of the period.

Martyrdom · Polycarp of Smyrna

Thecla hears Paul preach, breaks her engagement, follows him, and survives repeated attempts to kill her, at one point baptising herself in a pool of man-eating seals. It is not historical reporting. Some in the early church read it as edifying fiction and others treated it as authority, and Tertullian complains about people using it to argue that women may baptise. The self-baptism has no parallel in the New Testament, which is part of why it was argued over. What it is good for is showing how ordinary Christians imagined discipleship, and how they remembered women who chose the church over family and class.

Written against the gnostics, and it does far more than refute them. Irenaeus argues that one God made the world and redeemed it, that the Old and New Testaments tell a single story, and that Christ sums up and repairs in himself everything Adam lost. He is also the first clear witness we have to a fourfold gospel.

Gnosticism · Irenaeus of Lyons · Recapitulation · The rule of faith

Tertullian coined or fixed much of the language the western church still uses, including the word trinity and the formula of three persons in one substance. He was combative and brilliant, and he ended up leaving the mainstream church for the rigorist Montanists, which tells you something about where his instincts ran.

Persona · Tertullian · The Trinity

Perpetua was a well-born young woman with a baby still feeding. Felicity was a slave who gave birth in prison days before they died. Part of the account is presented as Perpetua's own writing, including her visions and the awful scenes with her father. Whatever an editor did to it afterwards, it is an extraordinary document.

Martyrdom

Origen was the most learned Christian of his age and the most argued over. He read scripture on several levels, held that the Son is begotten eternally, and speculated about things the later church rejected. Parts of his thought were condemned centuries after he died. Almost everyone who came after him worked with tools he made.

Allegory · Eternal generation · Origen of Alexandria

Decius required everyone to sacrifice and produce a certificate. Plenty of Christians complied, and then wanted to come back. Could they? On what terms? Whether serious sin after baptism could be forgiven, and how often, split churches for decades. It is one of the oldest live arguments in Christian history and it has never really stopped.

The lapsed · Novatianism · Penance

Novatian held that the church had no power to restore those who had cracked. Cyprian and the majority held that it did, after penance. The rigorists were not obviously wrong about holiness, and they lost anyway. The church chose to be a body with room for the failed, and that choice shaped the doctrine of penance for the next thousand years.

Cyprian of Carthage · Novatianism · Penance

Cyprian led the African church through persecution and the mess that followed, and wrote On the Unity of the Catholic Church in the middle of it. His line that there is no salvation outside the church, and his insistence that the bishops together hold the church's unity, set the terms for western thinking about ministry.

Cyprian of Carthage · Episcopacy

Diocletian ordered scriptures burned, buildings pulled down and clergy arrested. It was severe, it was sustained, and it failed. It also left behind the Donatist controversy, because somebody had to decide what to do with the clergy who had handed the scriptures over.

Donatism

Within a year of the persecution ending, the empire has a ruler who favours the church. The consequences are enormous and they cut both ways. Persecution stops, buildings and money arrive, and the church takes on a relationship with state power that it has been arguing about ever since. The two accounts we have of what he saw do not agree, and the earlier one is the plainer.

Constantine · Constantinianism

Constantine and Licinius agree toleration for all religions, Christianity included, and order confiscated property handed back. Galerius had already stopped the persecution two years earlier. This is toleration, not establishment. Christianity does not become the official religion of the empire until Theodosius in 380.

Constantine

Arius was trying to protect the oneness and the otherness of God. If the Son is begotten, he reasoned, then he had a beginning, and so he stands on the creature side of the line between God and everything else. The argument spread at astonishing speed, and it forced the church to say what it had always assumed and never defined.

Arianism · Arius · Homoousios

Around three hundred bishops, summoned by an emperor, adopt a creed with one deliberately unbiblical word in it. Homoousios, of the same substance. The word was picked precisely because no Arian could sign it. Nicaea did not end the controversy. Most of the next sixty years went on fighting about what it had actually meant.

Council · Homoousios

Athanasius held the see for forty five years and spent seventeen of them in exile. His argument was never mainly philosophical. It was about salvation. Only God can save, and only what God has taken on can be healed. So if the Son is a creature, nobody is saved.

Athanasius of Alexandria · Deification · Soteriology

The dating is genuinely contested, with serious arguments for a young Athanasius before Nicaea and a mature one after. The argument runs through what has been called the divine dilemma. God's justice means death has to follow sin, and God's goodness will not let his own image be destroyed, so the Word takes a body that can die and dies in it. Its place on this line is the later date, which is a choice between two and not a verdict.

Athanasius of Alexandria · Deification · The divine dilemma

The thirty ninth Festal Letter went out to set the date of Easter, and in it Athanasius names the books to be read as scripture. It is the earliest list identical to the present New Testament. Worth noticing what it is not. It is not a council inventing a canon. It is a bishop writing down what the churches had come to receive.

Athanasius of Alexandria · Canon

Basil of Caesarea, his brother Gregory of Nyssa and his friend Gregory of Nazianzus pulled the words ousia and hypostasis apart, so that one being in three persons could be said without contradicting itself. They also argued for the full divinity of the Spirit, which Nicaea had barely touched.

Basil of Caesarea · Gregory of Nazianzus · Gregory of Nyssa · Hypostasis · Ousia · Pneumatology

The council reaffirmed Nicaea and filled out the article on the Holy Spirit, who is worshipped and glorified together with the Father and the Son. What came out of it is what people usually mean when they say the Nicene Creed. The filioque clause, which later divided east and west, is not in it.

Filioque · Pneumatology

Augustine's own account in the Confessions, the child's voice in the garden and the opened Paul, is one of the most read passages in Christian writing. Almost everything the western church argued about afterwards runs through him. Grace, sin, the will, time, the church, the state.

Augustine of Hippo · Grace · Original sin

Rome had not been taken by a foreign army in eight hundred years. Pagan critics said it happened because the old gods had been dropped. Augustine's answer took him the next sixteen years and became The City of God.

Augustine of Hippo · The two cities

Pelagius was a serious moralist. He held that God would not command what people cannot do, so the will must be free enough to obey. Augustine held that the will itself is damaged and needs grace before it can even want the good. The church sided with Augustine. How far it went with him has been argued ever since.

Free will · Grace · Original sin · Pelagianism

The earthly city is built by love of self to the point of contempt for God. The heavenly city by love of God to the point of contempt for self. They are mixed together until the end and cannot be sorted now. It is the founding text of Christian political thought in the west, and it is far more careful than most of what has been built on it.

Augustine of Hippo · The two cities

Nestorius objected to calling Mary God-bearer and preferred Christ-bearer. Cyril of Alexandria argued that the title says something about the unity of Christ's person, not something about Mary's honour. If the one born of her is not God, then God did not truly become human. The council agreed with Cyril.

Cyril of Alexandria · The hypostatic union · Nestorianism · Nestorius · Theotokos

Chalcedon defined that Christ is fully God and fully human in one person, and it did it mostly by ruling out the wrong answers rather than explaining how. It is still the standard of orthodoxy for Catholic, Orthodox and most Protestant churches. It also caused a permanent split, and the Oriental Orthodox churches have never received it.

The Chalcedonian Definition · The hypostatic union · Monophysitism

Orange affirmed that even the beginning of faith is a gift, which ruled out the idea that a person makes the first move and God supplies the rest. It also declined to follow Augustine into double predestination. The Reformers appealed to it heavily a thousand years later.

Grace · Prevenient grace · Semi-Pelagianism

Benedict wrote a rule notable mostly for its moderation. Prayer, work and study in balance, and an abbot who is bound to listen to the youngest brother in the house. Monasteries built on it carried literacy, agriculture and libraries through the collapse of the western empire.

Monasticism

Gregory's Pastoral Rule, on how to care for different kinds of people differently, was the standard handbook for clergy for centuries. He also sent Augustine of Canterbury to Kent in 597. He is a useful corrective to the idea that the medieval papacy was only ever about power.

Gregory the Great

Syria, Egypt and North Africa, the places that produced Athanasius, Augustine, Cyril and a great deal of the church's early thinking, pass out of Christian political control. The centre of Christian gravity moves north and west. It is one of the most consequential facts in church history and it gets skipped constantly.

The monothelite compromise said Christ has two natures but one will. Maximus argued that a nature without a will is not a real nature, so a Christ without a human will has not truly become human. He was mutilated and exiled for saying so. The Third Council of Constantinople vindicated him in 681, nineteen years after he died.

Dyothelitism · Maximus the Confessor · Monothelitism

Northumbria had two Christian traditions running on different calendars, one from Iona and the Celtic mission, one from Rome. The king's own court sometimes kept Easter twice in the same year. At a synod hosted by the abbess Hilda, Wilfrid argued for Roman practice on the dating of Easter and the shape of the tonsure, invoking the authority of Peter, and King Oswiu ruled for Rome. The Ionan party did not simply disappear, but the decision set the Northumbrian, and eventually the English, church on a Roman trajectory rather than a Celtic one.

Hilda of Whitby

Iconoclasts read the second commandment as forbidding images. John of Damascus answered that the incarnation changes the question, because God has taken visible matter to himself. The Second Council of Nicaea in 787 permitted icons, drawing a line between veneration and worship. In the east the argument is a christological one wearing an artistic coat. The later Reformed objection to images is a different argument, made from the second commandment.

Iconoclasm · The Incarnation · John of Damascus

Mutual excommunications in 1054 are the conventional marker. The real separation was slow and cumulative. Language, the filioque added to the creed in the west, the authority of the pope, and the sack of Constantinople by western crusaders in 1204, which did more damage than any argument about doctrine.

Filioque · Orthodoxy

Anselm reframed the atonement around satisfaction. Sin dishonours God infinitely, humanity owes what it cannot pay, and the God-man pays it. Earlier writers had mostly spoken of ransom, or of victory over the devil. Anselm's account shaped western thinking about the cross for the next nine hundred years.

Anselm of Canterbury · Atonement · Satisfaction

Aquinas took the newly recovered Aristotle and put him to work in Christian theology, arguing that grace does not destroy nature but perfects it. He stopped writing months before he died, saying that what he had seen made everything he had written look like straw.

Analogy · Thomas Aquinas · Natural theology · Scholasticism

Wycliffe and his circle produced the first complete English Bible, translated from the Latin Vulgate rather than from the original languages. The authorities were hostile and owning a copy could be dangerous. He was condemned decades after his death, and his bones were dug up and burned.

Vernacular · John Wycliffe

Hus preached against clerical corruption, and his followers pressed for communion in both kinds for the laity, which he endorsed from prison. He came to the Council of Constance under imperial protection and was condemned and burned. A century later Luther, told he was arguing like Hus, went away, read him, and decided he agreed.

Jan Hus · Martin Luther

The immediate consequence for theology was the arrival in Italy of Greek texts and the people who could read them. Within two generations western scholars were reading the New Testament in Greek rather than only in Latin, and that is one of the conditions the Reformation grew out of.

Printing did not cause the Reformation, but the Reformation is very hard to imagine without it. Luther's tracts sold in enormous numbers and could not be shut down by seizing one copy. The same technology put the Bible in ordinary hands, which changed who was allowed to have an opinion about it.

Erasmus printed the Greek text with a fresh Latin translation beside it. Where the Vulgate had told priests to do penance, the Greek said repent. Where it read full of grace, the Greek said favoured one. Small differences with very large consequences. And Luther read them.

Desiderius Erasmus · Renaissance humanism · Textual criticism

The theses are narrower than their reputation. They attack the sale of indulgences, not the papacy and not the mass. What made them explosive was printing, timing and the reaction. Luther expected a university debate and got a continental crisis. Whether he nailed them to the church door is less certain than the date. What is not in doubt is that he sent them to his archbishop on the thirty first of October.

Indulgence · Justification · Martin Luther

Luther asked to be shown from scripture and plain reason where he was wrong, and said that going against conscience is neither right nor safe. The famous words about standing here may well be a later addition. The principle underneath, that scripture stands over councils and popes, is the part that mattered.

Martin Luther · Sola scriptura

Tyndale translated from the original languages and wrote English prose of astonishing quality. A great deal of the King James Version is simply his, often word for word. He was strangled and burned in 1536. His last reported prayer was that God would open the king of England's eyes.

William Tyndale · Vernacular

Presented to the emperor by Lutheran princes, and drafted to show that the reformers were catholic Christians rather than radicals. It is the first of the great Protestant confessions, and it set the pattern. When the church divides, both sides start writing.

Confession · Philip Melanchthon

The Institutes began as a short handbook for people reading scripture and grew into the most systematic statement of Reformed theology there is. Union with Christ does a great deal of the work in it, with justification and sanctification both flowing from that. Whether that or predestination is the controlling idea is argued.

John Calvin · Predestination · Union with Christ

Trent defined justification, the sacraments, scripture and tradition, and its canons condemn specific Protestant propositions by name. It also cleaned up the abuses that had provoked the crisis, ending the sale of indulgences and requiring seminaries. It fixed Catholic doctrine for four hundred years.

Justification · Tradition

Cranmer's gift was for prose that ordinary people could say out loud, over and over, without it wearing out. The 1662 book remains one of the Church of England's doctrinal standards, alongside the Thirty Nine Articles and the Ordinal. Much of what English speakers assume is the natural sound of prayer is his.

Thomas Cranmer · Liturgy

Forty seven scholars working in six companies, leaning heavily on Tyndale. It was not universally welcomed at first and took decades to push out the Geneva Bible. Its long dominance shaped English prose and the religious imagination of the whole English-speaking world.

William Tyndale · Vernacular

The Remonstrants had raised five objections to the Reformed teaching on grace and election as it was then held in the Dutch church. Dort answered each of them, though the Remonstrants attended as defendants rather than as members and were dismissed before the verdict. The answers were later summarised, long afterwards and in English, by the acronym TULIP. The acronym is a much later teaching device, not a product of the synod.

Arminianism · John Calvin · Predestination

Produced by an assembly the Long Parliament convened during the civil war. The Confession and the two Catechisms are still doctrinal standards for Presbyterian churches around the world. The Shorter Catechism opens by asking what the chief end of man is, and answers, to glorify God and enjoy him for ever.

Confession · Predestination

Wesley, Whitefield and Edwards, pulling in different directions and often disagreeing sharply, produced a movement that reshaped English-speaking Protestantism. They divided over predestination, and over slavery, which Wesley attacked and Whitefield defended. The emphasis on personal conversion, assurance and lay activity is the root of what is now called evangelicalism.

Conversion · Jonathan Edwards · Evangelicalism · John Wesley

Carey's Enquiry answered the view that the command to make disciples had already been discharged by the apostles. The nineteenth century missionary movement that followed is why the church today is largest in Africa, Asia and Latin America. Its entanglement with empire is a real and serious part of the story.

The Great Commission · Mission

Writing for educated people who had stopped taking Christianity seriously, Schleiermacher put religion in a feeling of absolute dependence. He is usually called the father of modern liberal theology. Whether he rescued the faith for a sceptical age or gave away too much is one of the long arguments of the last two centuries.

Liberal theology · Friedrich Schleiermacher

Source criticism, the documentary hypothesis in the Old Testament, the quest for the historical Jesus in the New. Some of it was driven by hostility to faith. Much of it was ordinary scholarly curiosity. Any theology degree taught today is downstream of these methods, whether it accepts their conclusions or not.

The documentary hypothesis · Higher criticism · The quest for the historical Jesus

The definition is narrower than it is usually taken to be. It covers formal pronouncements on faith and morals made by the pope speaking as universal pastor, and it has been used very rarely. The council was suspended when Italian troops entered Rome.

Papal infallibility

Led by William Seymour, the son of former slaves, the Azusa Street revival was racially mixed at a time when almost nothing else in America was. Pentecostal and charismatic Christianity is now the fastest growing part of the world church and a great deal of it traces back here. The mixing did not last. Within a decade the movement had divided along the colour line like almost everything else in America.

Pentecostalism · Pneumatology

Barth had watched his teachers sign up to support the war in 1914 and concluded that their theology had nothing to stand on. Romans insists that God is God and not the highest human value, and that revelation comes from outside rather than up out of religious experience. It set the agenda for a century.

Karl Barth · Neo-orthodoxy · Revelation

Drafted largely by Barth, Barmen rejected the claim that the church could have any source for its preaching besides the Word of God, or any other lord besides Jesus Christ. It is short. It is also the clearest modern statement of what a confessing church is for.

Karl Barth · Dietrich Bonhoeffer

Mass in the language people actually speak, a renewed emphasis on scripture, a fresh account of the church as the people of God, and a decisive change of posture towards other Christians and other faiths. How to read it is still contested inside Catholicism, which is a sign of how far it reached.

Ecumenism · Liturgy

Drafted with John Stott heavily involved, Lausanne affirmed both evangelism and social responsibility as Christian duty, healing a split that had run for most of the century. It also marked the arrival of non-western voices, Rene Padilla and Samuel Escobar among them, at the centre of the evangelical conversation.

Evangelicalism · Mission

In 1900 the great majority of Christians lived in Europe and North America. Today the majority live in Africa, Latin America and Asia, and that is where the largest congregations, the fastest growth and a growing share of the theological work are. It is the biggest single fact about the church in the last hundred years.

World Christianity