Christianity

Christianity is an Abrahamic monotheistic religion, which states that Jesus is the Son of God and rose from the dead after his crucifixion, whose coming as the messiah (Christ) was prophesied in the Old Testament and chronicled in the New Testament. It is the world's largest and most widespread religion with over 2.3 billion followers, comprising around 28.8% of the world population. Its adherents, known as Christians, are estimated to make up a majority of the population in 120 countries and territories.

Christianity remains culturally diverse in its Western and Eastern branches, and doctrinally diverse concerning justification and the nature of salvation, ecclesiology, ordination, and Christology. Most Christian denominations, however, generally hold in common the belief that Jesus is God the Son—the Logos incarnated—who ministered, suffered, and died on a cross, but rose from the dead for the salvation of humankind; this message is called the gospel, meaning the "good news". The four canonical gospels of Matthew, Mark, Luke and John describe Jesus' life and teachings as preserved in the early Christian tradition, with the Old Testament as the gospels' respected background.

Christianity began in the 1st century, after the death of Jesus, as a Judaic sect with Hellenistic influence in the Roman province of Judaea. The disciples of Jesus spread their faith around the Eastern Mediterranean area, despite significant persecution. The inclusion of Gentiles led Christianity to slowly separate from Judaism in the 2nd century. Emperor Constantine I decriminalized Christianity in the Roman Empire by the Edict of Milan in 313 AD. Later, Constantine convened the Council of Nicaea in 325 AD, where the Nicene Creed was adopted, and where Early Christianity was consolidated into what would become the state religion of the Roman Empire by around 380 AD. The Church of the East and Oriental Orthodoxy both split over differences in Christology during the 5th century, while the Eastern Orthodox Church and the Catholic Church separated in the East–West Schism in the year 1054. Protestantism split into numerous denominations from the Catholic Church during the Reformation era (16th century). Following the Age of Discovery (15th–17th century), Christianity expanded throughout the world via missionary work, evangelism, immigration, and extensive trade. Christianity played a prominent role in the development of Western civilization, particularly in Europe from late antiquity and the Middle Ages.

The three main branches of Christianity are Catholicism (1.3 billion people), Protestantism (800 million), and Eastern Orthodoxy (300 million), while other prominent branches include Oriental Orthodoxy (60 million) and Restorationism (35 million). Smaller church communities number in the thousands. In Christianity, efforts toward unity (ecumenism) are underway. In the West, Christianity remains the dominant religion even with a decline in adherence, with about 70% of that population identifying as Christian. Christianity is growing in Africa and Asia, the world's most populous continents. Many Christians are still persecuted in some regions of the world, particularly where they are a minority, such as in the Middle East, North Africa, East Asia, and South Asia.

Early Jewish Christians referred to themselves as being of 'The Way' (Koine Greek: τῆς ὁδοῦ, romanized: tês hodoû), an expression possibly coming from Isaiah 40:3, "prepare the way of the Lord". According to Acts 11:26, the term "Christian" (Χρῑστῐᾱνός, Khrīstiānós), meaning "followers of Christ" and referring to Jesus' disciples, was first used in the city of Antioch by the non-Jewish inhabitants there. The earliest recorded use of the term "Christianity/Christianism" (Χρῑστῐᾱνισμός, Khrīstiānismós) was by Ignatius of Antioch around 100 AD. The name Jesus comes from Ancient Greek: Ἰησοῦς Iēsous, probably from Hebrew/Aramaic: יֵשׁוּעַ Yēšūaʿ.

Christianity developed during the 1st century AD in Judaea as a Jewish Christian sect with Hellenistic influence of Second Temple Judaism. An early Jewish Christian community was founded in Jerusalem under the leadership of the three Pillars of the Church, namely James the Just, Peter, and John.

Jewish Christianity soon attracted Gentile God-fearers, posing a problem for its Jewish religious outlook, which insisted on close observance of the Jewish commandments. Paul the Apostle solved this by insisting that salvation by faith in Christ, and participation in his death and resurrection by their baptism, sufficed. At first he persecuted the early Christians, but after a conversion experience he preached to the gentiles, and is regarded as having had a formative effect on the emerging Christian identity as separate from Judaism. Eventually, his departure from Jewish customs would result in the establishment of Christianity as an independent religion.

This formative period was followed by the early bishops, whom Christians consider the successors of Christ's apostles. From the year 150, Christian teachers began to produce theological and apologetic works aimed at defending the faith. These authors are known as the Church Fathers, and the study of them is called patristics. Notable early Fathers include Ignatius of Antioch, Polycarp, Justin Martyr, Irenaeus, Tertullian, Clement of Alexandria and Origen.