Two thousand years ago, a Galilean preacher was executed by Rome as a provincial troublemaker. His followers insisted he had risen from the dead — and built, on that conviction, the largest faith in human history.
The faith in images
Origins
The story begins in a backwater of the Roman Empire. Jesus of Nazareth preached in Galilee and Judea for — tradition suggests — some three years, gathered twelve apostles, and was crucified under the prefect Pontius Pilate; tradition places his death at about 30–33 CE. Within days, his followers claimed he had risen — and the claim, not the execution, became the story. At Pentecost, as tradition tells it, the apostles preached in Jerusalem to pilgrims from across the known world, and the first Christian community was born.
The faith spread the way ideas spread in an empire built of roads: along them. Paul of Tarsus carried the message to the Gentiles in a string of epistles; house churches multiplied in Antioch, Alexandria, Ephesus, and Rome itself. Rome answered with persecution — Nero blamed Christians for the fire of 64 CE; Diocletian launched the Great Persecution in 303 — and answered badly: the martyrs made magnificent witnesses, and by the century’s end Christians were perhaps a tenth of the empire’s people. Estimates vary, but the trajectory was unmistakable.
Golden ages
Then the empire surrendered. As tradition tells it, Constantine saw a cross of light before the battle of the Milvian Bridge in 312; in 313 his Edict of Milan made Christianity legal, and in 325 the Council of Nicaea fixed its creed. In 380 Theodosius I made it the state religion of Rome — the persecuted had become the establishment in a single lifetime. Basilicas rose over the empire’s forums, and the Church organized itself with imperial efficiency: bishops, councils, canon law.
Out of that union came a civilization’s worth of culture. Monks like Anthony of Egypt and Benedict of Nursia built communities that preserved ancient learning through centuries when no one else would; Augustine of Hippo wrote theology that still anchors Western thought; missionaries carried the faith past the empire’s frontiers — Patrick to Ireland in the fifth century, Cyril and Methodius to the Slavs in the ninth. In Constantinople, Justinian raised the Hagia Sophia in 537, and the medieval universities — Bologna, Paris, Oxford — were, in their founding, Christian institutions, where Thomas Aquinas set faith and reason in a grand, uneasy synthesis.
And there were the Crusades — called by Urban II in 1095, Jerusalem taken in 1099, lost again to Saladin in 1187, the last crusader port of Acre falling in 1291. Two centuries of holy war that shaped the medieval imagination: castles and chivalry on one side, a deep wound in Christian-Muslim relations on the other — a wound whose history both sides remember, and remember differently.
Trials
The faith’s fractures were often self-inflicted. In 1054 the mutual excommunications of Rome and Constantinople split Christianity into Catholic West and Orthodox East — the Great Schism, over doctrine, authority, and pride. And in the seventh century a greater shock had arrived from outside: Islam rose in Arabia, and within a generation Christians had lost the Levant, North Africa, and most of Spain — lands that had been the faith’s heartland. Christendom contracted to Europe and learned to live as one civilization among several.
Then the Reformation split the West itself. In 1517 Martin Luther nailed — or, as historians now caution, quite possibly mailed — his ninety-five theses to the debate at Wittenberg; within a decade Calvin was building a theocratic Geneva and Henry VIII had made himself head of the Church of England in 1534. Europe’s wars of religion followed: the Thirty Years’ War of 1618–1648 devastated the German lands, and the Peace of Westphalia of 1648 finally conceded that Christians would have to live side by side with other Christians.
Modernity brought new trials. The Russian Revolution of 1917 unleashed the twentieth century’s fiercest anti-religious campaigns; Christianity went underground in the Soviet Union and China — and survived. And the Church reformed itself from within: the Second Vatican Council of 1962–1965 opened the windows, as John XXIII put it, trading Latin for the vernacular and confrontation for dialogue.
Today
There are more Christians alive today than there were human beings of any faith in 1900 — the faith has grown, in one century, by more than the entire population of the earth at the century’s start.
Today Christianity counts some 2.4 billion followers — about a third of humanity, the largest faith on earth. About 1.4 billion are Catholics under the Bishop of Rome; some 900 million belong to Protestant and independent churches; roughly 300 million to the Eastern Orthodox churches. Latin America is its Catholic heartland; sub-Saharan Africa its fastest-growing frontier, where Pentecostal congregations fill stadiums; and in the Middle East, ancient communities that have prayed in Aramaic since the first centuries hold on in diminished numbers.
The faith’s geography has inverted: its future is African, Asian, and Latin American, while its old European heartland secularizes — churches full in Seoul and Nairobi, half-empty in Amsterdam. Ecumenical dialogue has softened the old schisms without erasing them. And the calendar still bears the faith’s imprint on believers and unbelievers alike: two millennia after a Galilean execution, a third of humanity still orders its week around Sunday.