History of Christianity

Origins and early expansion

Christianity took shape in the context of Second Temple Judaism. Followers of Jesus, including the twelve apostles and other disciples, preached that he was the Messiah and called people to repentance and ethical reform. Early decisions about how non-Jewish converts might join the movement—most notably addressed in gatherings such as the Council of Jerusalem—helped the community grow beyond Jewish ethnic boundaries. Persecutions and conflicts with some Jewish authorities and Imperial officials occurred, and accounts of early martyrs and missionary journeys helped spread belief in Jesus throughout the Mediterranean world.

Doctrine, worship and institutions

Over time the movement produced an authoritative collection of scriptures, liturgical practices, and theological formulations. Worship commonly centers on baptism and the Eucharist (Communion), and most traditions recognize a creedal summary of beliefs about the nature of God and Christ established by ecumenical councils. Clergy, episcopal structures, monasteries and schools became important for teaching, pastoral care and preserving texts. The development of theology and canon law continued through debates about Christology, the Trinity and other matters.

Schisms, reform and major branches

Christianity has experienced divisions and reform movements that shaped its landscape. The early centuries saw doctrinal controversies resolved at ecumenical councils; later large-scale splits produced the principal families of churches: the Roman Catholic Church in Western Europe, the Eastern Orthodox communion centered in Byzantium and later national churches, the Oriental Orthodox bodies that separated earlier over Christological disputes, and numerous Protestant traditions that emerged after the 16th-century Reformation. Each branch preserved core Christian claims while differing in theology, liturgy and governance.

Global spread and cultural impact

From the Middle Ages onward Christianity spread through conversions, political change and missionary activity into Northern and Eastern Europe, Russia, Africa, the Americas and Asia. During the Age of Exploration and colonial periods missionaries established churches and institutions worldwide. Christianity has influenced art, education, law, social welfare, and public holidays, and today it remains the largest single religious tradition in terms of adherents, expressed in great diversity of languages and cultures.

Key names, places and terms

• Christianity: the faith and practices rooted in Jesus.
• religion: a system of belief and worship.
• church: organized congregations and institutions.
• Jesus: central figure whose life and teaching are foundational.
• apostles: early messengers and leaders who spread the message.
• death: crucifixion is a focal event in Christian narratives.
• resurrection: claim that Jesus rose, central to Christian hope.
• small group: early Christian communities were initially compact.
• Judea: region where the movement began.
• Roman Empire: the political framework for early expansion.
• persecution of Christians: periodic opposition by authorities.
• state religion: later adoption by some empires and kingdoms.
• Middle Ages: period of institutional consolidation in Europe.
• Northern Europe: region converted during medieval centuries.
• schisms: formal splits within the church.
• theological: relating to doctrines and beliefs.
• Oriental Orthodoxy: family of ancient eastern churches.
• Protestant churches: traditions that emerged from Reformation critiques.
• ethnically: many early adherents were Jewish by ethnicity.
• proselytes: converts from other groups.
• St. Peter: an influential early leader in tradition and history.
• Council of Jerusalem: early meeting addressing Gentile converts.
• martyrdom: witness unto death that inspired later believers.
• Stephen: traditionally counted among the first Christian martyrs.
• synagogues: Jewish places of assembly that related to early churches.
• Christian: name applied to followers of Christ.
• Greek: language important for early Christian writings and terms.
• disciples: learners and followers of Jesus who formed the first communities.
• Antioch: an early center where the name "Christian" was first used.