# How Christianity grew and split From the Edict of Milan through the councils, the Great Schism, the Reformation, and the modern movements, Mormonism included. *This story part of: Religion and ideology* *Easter, Lent, and the roots of the spring festival part of this story* *The Renaissance: the rebirth of antiquity led to this story* *Paganism: the old religions, their fall, and their return parallel this story* *Zoroastrianism: heaven, hell, and the first cosmic battle led to this story* *Ethiopia: the empire that was never colonized part of this story* ## c. 50 — The Council of Jerusalem About AD 50 the apostles and elders meet at Jerusalem to decide whether Gentile converts must keep the law of Moses. Acts 15 records their decision that they need not be circumcised. ## c. February 313 — Edict of Milan Constantine and Licinius agree to tolerate Christianity throughout the Roman Empire, ending official persecution. Christianity moves from outlawed sect toward imperial religion, binding church and European power for over a millennium. ## 20 May 325 — First Council of Nicaea Constantine convenes the first ecumenical council; it produces the Nicene Creed and the first church-wide definition of orthodox Christian doctrine, condemning Arianism. ## 27 February 380 — Christianity becomes Rome's state religion Emperor Theodosius I issues the Edict of Thessalonica, making Nicene Christianity the official religion of the Roman Empire. Other Christian sects and pagan cults lose imperial favor. ## May 381 — First Council of Constantinople The second ecumenical council expands the Nicene Creed, affirming the divinity of the Holy Spirit. The revised creed is still recited in most Christian churches. ## 22 June 431 — Council of Ephesus The third ecumenical council condemns Nestorius and affirms Mary's title Theotokos, bearer of God. The dispute drives the Church of the East into a lasting separate existence. ## 8 October 451 — Council of Chalcedon The fourth ecumenical council defines Christ as one person in two natures, divine and human. Churches in Egypt, Syria, and Armenia reject the formula, creating the Oriental Orthodox split that endures today. ## c. 529 — Benedict founds Monte Cassino Benedict of Nursia establishes his monastery at Monte Cassino and writes his Rule for monastic life. The Rule becomes the template for Western monasticism for a thousand years. ## 3 September 590 — Gregory the Great becomes pope Gregory I takes office and turns the papacy into a governing institution, administering Rome, negotiating with kings, and sending missionaries to England. His pontificate is widely seen as the moment the medieval papacy takes shape. ## 16 July 1054 — Great Schism of 1054 Papal legates excommunicate Patriarch Michael Cerularius in Hagia Sophia, and he responds in kind. The mutual excommunications come to mark the lasting break between Roman Catholic and Eastern Orthodox Christianity. ## 1309 to 1377 — Avignon papacy begins Pope Clement V moves the papal court to Avignon under French influence, where seven successive popes reside. The long absence from Rome damages papal prestige and helps trigger the Western Schism. ## 1378 to 1417 — Western Schism Rival popes in Rome and Avignon, later joined by a third line, each claim legitimacy and divide Catholic Europe. The Council of Constance ends the schism and strengthens the conciliar movement. ## 6 July 1415 — Jan Hus burned at Constance The Bohemian reformer Jan Hus is condemned for heresy and burned at the stake despite a promise of safe conduct. His death sparks the Hussite movement and foreshadows the Reformation a century later. > "Hus was burned at the stake. It was a powerful symbol that the institutional Church was no longer capable of dealing constructively with a movement of reform" > — A History of Christianity: The First Three Thousand Years, p. 596-599 ## 31 October 1517 — Luther posts the Ninety-five Theses Martin Luther publishes ninety-five theses against the sale of indulgences, traditionally by posting them on the castle church door. The protest ignites the Protestant Reformation and the permanent division of Western Christianity. ## 1 January 1519 — Zwingli begins the Reformation in Zurich Huldrych Zwingli starts preaching straight through the Gospel of Matthew at the Grossmunster, breaking with the church lectionary. His scripture-first program launches the Swiss Reformed branch of Protestantism independently of Luther. ## 21 January 1525 — First Anabaptist baptisms Conrad Grebel and companions rebaptize one another as believing adults, rejecting infant baptism. The act founds the Anabaptist movement, ancestor of the Mennonites, Amish, and Hutterites. ## November 1534 — Act of Supremacy creates the Church of England Parliament declares Henry VIII supreme head of the Church of England, severing it from papal authority. The break founds Anglicanism, driven by the king's annulment dispute as much as by doctrine. ## 13 September 1541 — Calvin establishes the Reformed church in Geneva John Calvin returns to Geneva and implements his Ecclesiastical Ordinances, organizing church and civic life around Reformed doctrine. Geneva becomes the model and training ground for Calvinist churches across Europe. ## 13 December 1545 to 1563 — Council of Trent The Catholic Church convenes a long council to answer the Reformation, defining doctrine on scripture, justification, and the sacraments and reforming clerical abuses. Trent shapes Catholicism for the next four centuries. ## 1609 — John Smyth founds the first Baptist congregation English separatist exiles led by John Smyth and Thomas Helwys adopt believer's baptism and form the first Baptist church. Helwys later carries the movement back to England. ## December 1620 — Pilgrims found Plymouth Colony Separatist Pilgrims arriving on the Mayflower establish Plymouth Colony after signing the Mayflower Compact. Their settlement begins the transplanting of English dissenting Protestantism to North America. ## June 1630 — Puritan migration to Massachusetts Bay John Winthrop's fleet brings roughly a thousand Puritans to found Massachusetts Bay Colony, envisioned as a godly commonwealth. The Great Migration that follows stamps Puritan religion on New England society. ## c. 1652 — George Fox founds the Quakers George Fox gathers the first large followings of the Religious Society of Friends, preaching direct inward experience of God without clergy or sacraments. The Quaker movement grows despite heavy persecution. ## c. 1730 to c. 1745 — First Great Awakening Revival preaching by Jonathan Edwards, George Whitefield, and others sweeps the American colonies, stressing personal conversion over formal religion. The awakening reshapes colonial Protestantism and boosts Baptist and evangelical growth. ## 24 May 1738 — John Wesley's Aldersgate experience John Wesley feels his heart 'strangely warmed' at a meeting on Aldersgate Street, an experience he counts as his evangelical conversion. The moment launches the Methodist revival movement within and eventually beyond the Church of England. ## c. 1790 to c. 1840 — Second Great Awakening Camp meetings and revivals spread evangelical Christianity across the young United States, fueling Methodist and Baptist expansion. The awakening also spawns reform movements and new denominations, including the restorationist churches. ## 6 April 1830 — Founding of the Church of Jesus Christ of Latter-day Saints Joseph Smith formally organizes the church shortly after publishing the Book of Mormon, which he presented as translated scripture. The new faith grows rapidly despite persecution and later migrates west to Utah. ## 21 May 1863 — Seventh-day Adventist Church organized Sabbatarian Adventists who emerged from the Millerite movement formally organize as the Seventh-day Adventist Church. Ellen G. White's writings become central to the denomination's identity. ## July 1879 — Russell founds the Watch Tower movement Charles Taze Russell publishes the first issue of Zion's Watch Tower, organizing the Bible Student movement. The group adopts the name Jehovah's Witnesses in 1931. ## 9 April 1906 — Azusa Street Revival A revival led by William J. Seymour breaks out and soon moves to a mission at 312 Azusa Street, marked by speaking in tongues and interracial worship. The meetings launch Pentecostalism, now one of Christianity's largest movements. ## 23 August 1948 — World Council of Churches founded Delegates from 147 Protestant, Anglican, and Orthodox churches establish the World Council of Churches. It becomes the main institution of the modern ecumenical movement. ## 11 October 1962 to 1965 — Second Vatican Council Pope John XXIII opens a council that modernizes Catholic practice, allowing Mass in local languages and opening dialogue with other faiths. Vatican II is the most sweeping reform of Catholicism since Trent.