Christianity

Christianity is an Abrahamic monotheistic religion centred on the belief that Jesus of Nazareth is the Son of God, the long-awaited Messiah whose life, death and resurrection bring salvation to humanity. Rooted in Jewish tradition and shaped by early Christian communities of the 1st century, it has grown into the world’s most widespread religion, practised by more than two billion adherents. Despite considerable doctrinal diversity, most Christian traditions uphold core beliefs centred on Jesus’ divine identity, his teachings, his crucifixion and his resurrection.

Core Beliefs and Scriptural Foundations

Christians affirm that Jesus is the incarnate Logos, the divine Word who took human form. His ministry, crucifixion and resurrection are viewed as the fulfilment of Old Testament messianic prophecies, and these events form the basis of Christian faith. The message of redemption through Jesus’ life and resurrection is known as the gospel, meaning “good news”.
The authoritative accounts of Jesus’ life and teachings appear in the four canonical gospels: Matthew, Mark, Luke and John. These writings are set against the background of the Hebrew Scriptures, with the Old Testament forming an essential foundation for Christian theology. Christian thought varies widely on topics such as justification, ecclesiology, ordination and the nature of Christ, yet remains anchored in the belief that Jesus’ sacrificial death restores the relationship between humanity and God.

Origins in the 1st Century

Christianity arose in the Roman province of Judaea during the 1st century AD as a Jewish sect within the milieu of Second Temple Judaism. The earliest followers of Jesus, including groups led by figures such as James the Just, Peter and John, were rooted in Jewish tradition and initially practised Jewish religious customs.
This early movement spread rapidly around the Eastern Mediterranean despite periods of local persecution. The inclusion of Gentile converts created significant debate regarding the necessity of observing Jewish laws. Paul the Apostle played a decisive role in affirming that faith in Christ and participation in his death and resurrection, particularly through baptism, were sufficient for salvation. This contributed to a gradual separation between Christianity and Judaism by the 2nd century.

Development in the Roman Empire

Christianity continued spreading through the Roman world, including regions in the Middle East, Asia Minor, North Africa and parts of Europe. Communities took root among Aramaic-speaking populations and within major urban centres. Intermittent waves of persecution occurred, though these were often regional and short-lived.
A turning point came in 313 AD when Emperor Constantine issued the Edict of Milan, decriminalising Christianity. Later in 325 AD, the First Council of Nicaea was convened, establishing foundational Christian doctrines. By the end of the 4th century, Christianity had become the official religion of the Roman Empire.
Alongside the rise of mainstream or “proto-orthodox” Christianity, various other groups flourished. These included Gnostic Christians, who emphasised dualistic beliefs and spiritual enlightenment. Such sects eventually declined as the developing orthodox tradition formalised its canon and theology.

Expansion and Schisms

As Christianity spread across continents, doctrinal and cultural differences led to major schisms. In the 5th century, disputes over Christological interpretations resulted in the separation of the Church of the East and the Oriental Orthodox Churches from the rest of Christendom.
The East–West Schism of 1054 divided Christianity into the Eastern Orthodox Church and the Catholic Church. Later, the Protestant Reformation in the 16th century created a wide range of Protestant denominations that diverged from Catholic doctrine.
Following the Age of Discovery, Christianity spread globally through missionary activity, trade and migration, establishing itself in the Americas, Africa, Asia and Oceania.
Today, the major branches of Christianity include:

• Catholic Church – the largest single Christian body, numbering more than one billion adherents.
• Protestantism – a broad family of churches with hundreds of millions of followers worldwide.
• Eastern Orthodoxy – comprising numerous autocephalous churches rooted in Byzantine tradition.

Other significant groups include the Oriental Orthodox Churches, Restorationist movements and the historic Church of the East.

Etymology and Early Identity

Early Jewish followers of Jesus sometimes referred to themselves as people of “The Way”, a phrase drawn from prophetic texts describing preparation for the Lord’s coming. The term “Christian” was first used in Antioch to describe the disciples of Jesus and soon became the accepted designation for his followers. By the early 2nd century, Christian writers such as Ignatius of Antioch were using the term Christianity to describe the faith itself.

Apostolic Age and Early Church Leadership

The formative period of early Christianity, often called the Apostolic Age, saw the rise of communities guided by apostles and early leaders regarded as the foundation of apostolic succession. From the mid-2nd century onward, Christian teachers produced theological, pastoral and apologetic literature.
These early thinkers, known collectively as the Church Fathers, included figures such as Ignatius of Antioch, Polycarp, Justin Martyr, Irenaeus, Tertullian, Clement of Alexandria and Origen. Their writings helped define doctrine, defend the faith and guide emerging communities.

Persecutions and Doctrinal Struggles

Christians experienced sporadic persecution under both Jewish and Roman authorities. Localised actions occurred during the 1st century, with some early believers executed for their teachings. In the 3rd century, the Decian persecution introduced an empire-wide decree requiring sacrifices to Roman gods. The most severe state-sponsored persecution, under Diocletian, began in 303 AD.
Despite these challenges, Christianity continued to grow. As doctrines developed, movements deemed heterodox by mainstream leaders were gradually excluded. Gnostic groups, which possessed distinct scriptures and beliefs, declined as the Church unified its teachings and canon. Jewish Christian groups that maintained observance of the Law of Moses also diminished by the 5th century.

Global Spread and Cultural Influence

Christianity spread throughout the Mediterranean world and beyond into areas controlled by the Parthian and Sasanian Empires. By the 1st and 2nd centuries, communities were already established in Egypt, with Alexandria becoming a major centre of learning. Later, Christianity reached regions such as North Africa, Ethiopia, Armenia, Georgia and India.
The religion played a decisive role in shaping Western civilisation, influencing law, ethics, art, education and political thought from late antiquity through the medieval period and into the modern era.
Today, it remains a major global faith, although its proportion has declined in many Western countries. Growth is particularly strong in Africa and Asia, which together form the most populous Christian regions of the future. In several parts of the world where Christians are minorities, they continue to face persecution.