“In the beginning was the Word, and the Word was with God, and the Word was God. […] And the Word became flesh and dwelt among us, and we beheld his glory.”
— John 1:1, 14
The claim
Christianity makes one large claim from which everything else follows: that in the person of Jesus of Nazareth, the eternal God entered human history, was crucified under Pontius Pilate, and was raised from the dead on the third day. This is not, for Christianity, a symbolic or mythological claim. It is a historical claim — not in the sense that it can be established by ordinary historical method (it cannot), but in the sense that the tradition’s entire self-understanding turns on whether something actually happened in the first third of the first century in Roman Judaea.
Everything else Christianity teaches — the Trinity, the Incarnation, the atonement, the Church, the sacraments, the moral vision, the hope of resurrection — is elaboration of, or consequence from, that core claim. Remove it and there is no Christianity.
History
Jewish roots and Jesus (1st c.)
Christianity emerges from Second Temple Judaism. Jesus of Nazareth is a Galilean Jew, probably born around 4 BCE, executed by Roman authorities around 30 CE. His teaching — preserved in the four canonical Gospels (Matthew, Mark, Luke, John, written between roughly 65 and 100 CE) — centers on the inbreaking kingdom of God, the love of God and neighbor, the inclusion of the outcast, and the authority of his own person as the one through whom God is acting. His followers experience him after his execution as alive, risen from the dead — an experience they narrate as encounters with a bodily but transformed person, not a ghost, not a mere memory, not a metaphor.
The earliest Christian community in Jerusalem consists of Jews continuing to worship at the Temple while meeting also for the distinctive Christian breaking of bread in memory of Jesus. Paul of Tarsus (c. 5–67 CE) — initially a persecutor of the movement, converted by a vision of the risen Christ — carries the message to gentiles and writes the earliest Christian literature we possess (his letters, c. 49–65 CE). The question of whether non-Jews must become Jews in order to become Christians is resolved at the Council of Jerusalem (c. 50 CE): they need not.
Imperial Christianity (2nd–5th c.)
The faith spreads across the Roman Empire despite periodic persecutions. By the early 4th century it is substantial enough that Constantine’s 313 Edict of Milan legalizes it; by 380 Theodosius makes it the official religion of the empire. The seven ecumenical councils (Nicaea I 325 through Nicaea II 787) define the Christian doctrinal core against various heresies. The Trinity (one God in three persons — Father, Son, Holy Spirit) and the two natures of Christ (fully divine and fully human, inseparable and unconfused) are the central clarifications. Major thinkers of this period include the Cappadocian Fathers (Basil, Gregory of Nazianzus, Gregory of Nyssa) and Augustine of Hippo in the Latin West.
The medieval period (6th–15th c.)
Western Europe re-Christianizes after the collapse of the Roman Empire. Monasticism, especially the Benedictine tradition, preserves learning and shapes the culture. The great schism between Eastern Orthodox and Roman Catholic churches culminates in 1054. Western scholastic theology reaches its summit in Thomas Aquinas (13th c.). The mystical tradition — Christian mysticism — flowers through the Rhineland masters (Eckhart, Tauler), the Beguines (Marguerite Porete, Hadewijch), the English contemplatives (Julian of Norwich, the Cloud of Unknowing), and the Spanish Carmelites (Teresa of Ávila, John of the Cross). Simultaneously, Christendom conducts the Crusades, the Inquisition, the forced conversions of Jews and Muslims — a record of violence that the tradition’s ethical teaching unambiguously condemns but that Christian institutions conducted.
The Reformations (16th–17th c.)
Martin Luther’s 1517 Ninety-Five Theses triggers the Protestant Reformation — a reform movement that rapidly becomes a division. Luther, John Calvin, Huldrych Zwingli, and others reframe Christian life around grace received by faith, scripture as final authority, and the priesthood of all believers. The Catholic response — the Counter-Reformation, the Council of Trent (1545–1563), the founding of the Jesuits — reforms from within while maintaining the essential medieval framework. The Church of England emerges as a distinct branch. The century of religious wars that follows kills millions and produces, eventually, the modern norms of religious toleration.
Modernity (18th c. – present)
Protestantism fragments into many denominations; the Anabaptist tradition (Mennonites, Quakers, later Baptists) develops without state establishment; the Methodist revival under Wesley reshapes English and American religion; the Catholic Church holds the First Vatican Council (1869–1870) and then, transformatively, the Second Vatican Council (1962–1965). Missionary activity spreads Christianity to Asia, Africa, and the Americas — simultaneously carrying the gospel and, often, colonial violence. The twentieth century’s upheavals — Communist persecution of Christians in Russia, Eastern Europe, and China; the Nazi genocide of Jews (which the churches’ response to was tragically inadequate); the liberation theology of Latin America; the civil rights movement in the United States; the Pentecostal expansion globally — remake the tradition again.
The twenty-first century sees Christianity’s demographic center shift decisively to the Global South. There are now more Christians in Africa than in Europe; Latin American and Asian Christianity are vigorously alive while parts of Europe secularize rapidly.
The major branches
- Eastern Orthodox — the Greek- and Slavic-language tradition of the Byzantine East. Roughly 230 million.
- Roman Catholic — the Latin-language tradition in communion with the Bishop of Rome. Roughly 1.3 billion — the largest Christian body.
- Oriental Orthodox — the non-Chalcedonian Eastern churches (Coptic, Ethiopian, Armenian, Syriac, Malankara). Roughly 60 million. In communion with each other but not with Eastern Orthodoxy due to a 5th-century Christological disagreement.
- Church of the East — the ancient Syriac-tradition church in Iraq, India, and diaspora. Small but continuous.
- Protestant — the post-Reformation Western churches. Enormously diverse: Lutheran, Reformed/Presbyterian, Anglican/Episcopal, Methodist, Baptist, Anabaptist, Pentecostal/Charismatic, and countless smaller denominations and independent congregations. Roughly 800 million.
- Restorationist / post-Protestant — Latter-day Saints, Jehovah’s Witnesses, and others who understand themselves as restorations of the primitive church. Their relationship to historic Christian orthodoxy is contested.
The core doctrines
The Trinity
God is one, and God is three Persons — Father, Son, and Holy Spirit — each fully God, each distinct, each eternally related to the others. This is the central doctrine clarified at Nicaea (325) and refined through the Cappadocian Fathers. It is not a numerical puzzle to be solved but the Christian grammar for speaking about a God who is inherently relational — who is love (1 John 4:8, 16) because love is what God eternally is among Father, Son, and Spirit, not a later activity added to a prior solitariness.
The Incarnation
“The Word became flesh and dwelt among us” (John 1:14). The eternal Son of God became fully human in Jesus of Nazareth — without ceasing to be fully divine. Not a god-man in the Greek sense, not a half-divine hero, not an especially enlightened teacher. The Chalcedonian definition (451): one person, two natures, “inconfusedly, unchangeably, indivisibly, inseparably.” This is what most scandalizes Jewish and Islamic interlocutors (who rightly recognize the magnitude of the claim) and what the Christian tradition insists cannot be softened without losing the faith’s substance.
The Atonement
Jesus’s death is understood to accomplish something on behalf of humanity — the classical language is salvation, redemption, atonement, reconciliation. Exactly how this works is disputed across a cluster of interpretive models (substitutionary, Christus Victor, satisfaction, moral exemplar, participation-in-Christ). The various traditions give differing weights to these; all hold that something of cosmic significance happened in the crucifixion.
The Resurrection
On the third day after his execution, Jesus was raised from the dead — not resuscitated (temporary return to the same life) but resurrected (the first instance of the new life awaiting all creation). The Christian claim is that this has already happened in Jesus and will be the final state of those who are in Christ. Paul: “If Christ has not been raised, our preaching is useless and so is your faith” (1 Cor 15:14). The entire tradition depends on this claim.
The Church and the sacraments
The community of those baptized into Christ — the Church — is, by Christian self-understanding, the continuing body of Christ in the world. The sacraments (differently numbered across traditions — seven in Catholic and Orthodox usage; two primary ones, baptism and eucharist, in most Protestant usage) are means by which God’s grace is made concretely available. The Eucharist — communion, the Mass, the Divine Liturgy, the Lord’s Supper — is the central Christian act, a participation in Christ’s self-giving that is simultaneously memorial, present participation, and anticipation of the final kingdom.
Practice
What is shared across all branches:
- Scripture — reading, hearing, studying, praying with the Bible. The specific canon and interpretive tradition varies by branch.
- Prayer — personal and communal, discursive and contemplative, spontaneous and liturgical. The Lord’s Prayer (Matthew 6:9–13, Luke 11:2–4) is the shared Christian prayer.
- Sacramental life — baptism (initiation), Eucharist (ongoing communion), and the other sacraments in their various traditions.
- Worship — corporate gathering for Word, sacrament, and song. Liturgical forms range from the elaborate Eastern Orthodox Divine Liturgy to the unprogrammed silence of Quaker meeting.
- Ethical formation — the life of love of God and neighbor, expressed in works of mercy, justice, chastity, honesty, forgiveness, and care for the poor.
- Contemplative practice — lectio divina, the Jesus Prayer, contemplative prayer, centering prayer, monastic hours, silent retreat.
- Fellowship — the life shared with other Christians, which the tradition regards as intrinsic to the faith, not optional.
Difficulties the tradition carries
The church’s history includes great goods — the preservation of learning, the development of hospitals and universities, the moral vocabulary of human rights, the sustained witness of countless ordinary and extraordinary Christians — and serious evils.
- Anti-Judaism and antisemitism. Christian supersessionist theology — the claim that the church replaces Israel — has fed centuries of hatred, violence, and eventual complicity in the Shoah. Post-Holocaust Christian theology (Vatican II’s Nostra Aetate, Protestant dialogue efforts, the formal repudiation of supersessionism by many major churches) represents the tradition’s reckoning with this, still incomplete.
- Colonialism and Christianization. Missionary activity has often accompanied conquest and the destruction of indigenous cultures. The tradition’s present-day Global South vitality is partly a testament to its capacity to be received anew in each culture; the past carries wounds its present must not forget.
- Crusades, Inquisition, religious war. Millennium-long stretches of church-sanctioned violence that the tradition’s own teaching condemns and that the institutional church has formally lamented (John Paul II’s 2000 “mea culpa”) without being able to undo.
- Sexual abuse. Substantial and sustained abuse of children by clergy in Catholic, Orthodox, and Protestant institutions, with institutional coverups. The response, across branches, has been uneven and insufficient.
- The woman question. Many branches of Christianity ordain women; many do not; the New Testament is read differently on this across the tradition. The historical exclusion of women from ecclesiastical authority is real; the contemporary movement to include them is also real.
- Denominational multiplication and schism. Protestantism in particular has fragmented into tens of thousands of denominations, each convinced of the scriptural warrant for its distinctives. The ecumenical movement of the twentieth century — the World Council of Churches, bilateral dialogues — has made real progress without resolving the fundamental division.
Living tradition
Approximately 2.4 billion Christians worldwide — the world’s largest religion, and growing globally despite European and American secularization. The tradition is most vibrantly alive in sub-Saharan Africa, Latin America, East Asia (particularly South Korea, China where practice is often underground, the Philippines), and in diaspora communities. North American and Western European Christianity faces distinctive challenges but also continued presence.
What the tradition says, it still says:
“Christ has died. Christ is risen. Christ will come again.”
— the memorial acclamation, said at every Eucharist across the Christian world