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 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. Following the Age of Discovery, 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, Protestantism, and Eastern Orthodoxy, while other prominent branches include Oriental Orthodoxy and Restorationism. Smaller church communities number in the thousands. In Christianity, efforts toward unity 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.
Etymology
Early Jewish Christians referred to themselves as being of 'The Way', an expression possibly coming from Isaiah 40:3, "prepare the way of the Lord". According to Acts 11:26, the term "Christian", 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" was by Ignatius of Antioch around 100 AD. The name Jesus comes from , probably from ''Yēšūaʿ.''History
Early Christianity
Apostolic Age
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.
Ante-Nicene period
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.Persecution of Christians occurred intermittently and on a small scale by both Jewish and Roman authorities, with Roman action starting at the time of the Great Fire of Rome in 64 AD. Examples of early executions under Jewish authority reported in the New Testament include the deaths of Saint Stephen and James, son of Zebedee. The Decian persecution was the first empire-wide conflict, when the edict of Decius in 250 AD required everyone in the Roman Empire to perform a sacrifice to the Roman gods. The Diocletianic Persecution beginning in 303 AD was also particularly severe. Roman persecution ended in 313 AD with the Edict of Milan.
While Proto-orthodox Christianity was becoming dominant, heterodox sects also existed at the same time, which held radically different beliefs. Gnostic Christianity developed a duotheistic doctrine based on illusion and enlightenment rather than forgiveness of sin. With only a few scriptures overlapping with the developing orthodox canon, most Gnostic texts and Gnostic gospels were eventually considered heretical and suppressed by mainstream Christians. A gradual splitting off of Gentile Christianity left Jewish Christians continuing to follow the Law of Moses, including practices such as circumcision. By the fifth century, they and the Jewish–Christian gospels would be largely suppressed by the dominant sects in both Judaism and Christianity.
Spread and acceptance in the Roman Empire
Christianity spread to Aramaic-speaking peoples along the Mediterranean coast and also to the inland parts of the Roman Empire and beyond that into the Parthian Empire and the later Sasanian Empire, including Mesopotamia, which was dominated at different times and to varying extents by these empires. The presence of Christianity in Africa began in the middle of the 1st century in Egypt and by the end of the 2nd century in the region around Carthage. Mark the Evangelist is claimed to have started the Church of Alexandria in about 43 AD; various later churches claim this as their own legacy, including the Coptic Orthodox Church. Important Africans who influenced the early development of Christianity include Tertullian, Clement of Alexandria, Origen of Alexandria, Cyprian, Athanasius, and Augustine of Hippo.File:Khor Virap Monastery and Mount Ararat, Armenia.jpg|thumb|The 7th-century Khor Virap monastery in the shadow of Mount Ararat; Armenia was the first state to adopt Christianity as the state religion in the early 4th century AD.
King Tiridates III made Christianity the state religion in Armenia in the early 4th century AD, making Armenia the first officially Christian state. It was not an entirely new religion in Armenia, having penetrated into the country from at least the third century, but it may have been present even earlier.
Constantine I was exposed to Christianity in his youth, and throughout his life his support for the religion grew, culminating in baptism on his deathbed. During his reign, state-sanctioned persecution of Christians was ended with the Edict of Toleration in 311 and the Edict of Milan in 313. At that point, Christianity was still a minority belief, comprising perhaps only 5% of the Roman population. Influenced by his adviser Mardonius, Constantine's nephew Julian unsuccessfully tried to suppress Christianity. On 27 February 380, Theodosius I, Gratian, and Valentinian II issued the Edict of Thessalonica establishing Nicene Christianity as the State church of the Roman Empire. As soon as it became connected to the state, Christianity grew wealthy; the Church solicited donations from the rich and could now own land.
Constantine was also instrumental in the convocation of the First Council of Nicaea in 325, which sought to address Arianism and formulated the Nicene Creed, which is still used by in Catholicism, Eastern Orthodoxy, Lutheranism, Anglicanism, and many other Protestant churches. Nicaea was the first of a series of ecumenical councils, which formally defined critical elements of the theology of the Church, notably concerning Christology. The Church of the East did not accept the third and following ecumenical councils and is still separate today by its successors.
In terms of prosperity and cultural life, the Byzantine Empire was one of the peaks in Christian history and Christian civilization, and Constantinople remained the leading city of the Christian world in size, wealth, and culture. There was a renewed interest in classical Greek philosophy, as well as an increase in literary output in vernacular Greek. Byzantine art and literature held a preeminent place in Europe, and the cultural impact of Byzantine art on the West during this period was enormous and of long-lasting significance. The later rise of Islam in North Africa reduced the size and numbers of Christian congregations, leaving in large numbers only the Coptic Church in Egypt, the Ethiopian Orthodox Tewahedo Church in the Horn of Africa and the Nubian Church in the Sudan.