The Christian religion had its origins in the life and teachings of Jesus of Nazareth, who lived in the region of Judaea in Palestine during the early years of the Roman Empire. Originally the belief of a small group of devout Jews in Jerusalem, Christianity gradually evolved during the course of the A.D. 300s into the official religion of the Roman Empire. It later spread beyond the Roman world, becoming the dominant faith in Europe during the Middle Ages.

Early Christians. After the death of Jesus around A.D. 30, his followers gathered in Jerusalem to prepare for his return to create the kingdom of God, which they believed was foretold in the Jewish scriptures, or sacred texts. At first, followers of Jesus preached his teachings only to their fellow Jews. However, some Christians, especially St. Paul, began converting Gentiles, or non-Jewish people, to the new faith. Thereafter, Christianity came to be viewed as a universal religion, open to men and women of any nation who were willing to follow the teachings of Jesus.

Early Christians formed ecclesiai (Greek word meaning “assemblies”), or churches, in various cities in the Near East. Missionaries traveled throughout the Roman empire spreading the faith in Greece, North Africa, and Rome itself. They were particularly successful in converting middle-class people in the cities. In addition to establishing churches, the early Christians developed a hierarchy of leadership and authority to help ensure the survival of the faith. Leaders of the church were called bishops. Believed to be the spiritual successors of Jesus’s apostles*, bishops were responsible for spreading and protecting Christian belief. The bishops of the leading religious centers—Rome, Jerusalem, Alexandria in Egypt, Antioch in Syria, and, after about A.D. 325, Constantinople—possessed more authority than other bishops. The bishop of Rome was considered to be the successor of St. Peter, the leading apostle of Jesus.

Early Christians wrote numerous accounts of Christ’s life and teachings, and apostles, such as Paul, wrote letters that circulated among the early Christian communities. Between the late A.D. 100s and 500s, church leaders compiled some of these writings as Christian scriptures to be used along with Jewish sacred writings. Later known as the New Testament, these writings served as the basis of the church’s missionary activities and liturgy*. The New Testament was later combined with the Jewish scriptures, or Old Testament, to form the Christian Bible.

* apostles early followers of Jesus who traveled and spread his teachings

* liturgy form of a religious service, including spoken words, songs, and actions

Differences in Belief. As Christianity spread, disagreements developed among Christians regarding the basic beliefs of the religion. Early Jewish Christians opposed St. Paul’s conversion of Gentiles. Gnosticism, a movement that arose in the A.D. 100s, emphasized the distinction between the physical and spiritual worlds and rejected attempts to build a religious community. Still other movements challenged the role of church leaders as the only guides to salvation*.

* salvation deliverance from the effects of sin, such as eternal punishment

One of the most serious disagreements among early Christians concerned the nature of God. Christians agreed that God existed in three ways—as God the Father, as Jesus the Son, and as the Holy Spirit—but they did not agree on the relationship among the three. During the A.D. 300s, some Christians followed a teacher named Arius, who taught that God the Father was the most important of God’s existences. This movement, known as Arianism, spread widely and threatened to undermine the authority of the church.

Councils of church leaders attempted to resolve the issue of God’s nature and relationship to Jesus Christ. The Council of Nicaea in A.D. 325 succeeded in adopting a statement of belief which became known as the Nicene Creed, an important part of official Christian doctrine*. The first Council of Constantinople in A.D. 381 ended the long controversy about the relationship of the Trinity—the union of the Father, Son, and Holy Spirit. The bishops decided that the Father, Son, and Holy Spirit were three equal existences of one God and that God and Christ were of one essence.

The decisions of these councils did not satisfy all Christians, however, and they resulted in divisions in the church. The Christians who lived in Egypt, known as the Copts, emphasized the unity of the human and divine qualities of Jesus Christ. When the Council of Chalcedon in A.D. 451 declared that Christ had two separate natures—God and man—and condemned the ruling division of the Coptic Church, most Copts formed an independent church and clergy.

Besides the councils, Christian beliefs were also defined by theological* works of Christian writers such as Origen, Tertullian, and St. Augustine. These theologians* provided a strong intellectual foundation for the development of Christian thought. However, beliefs that differed from those accepted by the leaders of the church were considered heresies*, and bishops often excommunicated* people who believed in these ideas.

Christianity and the Roman Empire. During the early years of Christianity, Roman authorities viewed Christians with suspicion, concerned about their potential to create social unrest. Although some early Christians were killed for their beliefs, widespread persecutions occurred infrequently. This situation changed during the early and mid-A.D. 200s, when the emperors Decius and Valerian persecuted Christians for their refusal to worship the pagan* Roman gods. Then in A.D. 303, the emperors Diocletian and Galerius issued a series of edicts* that began a period known as the Great Persecution. These edicts ordered the destruction of churches and the burning of sacred books. All clergymen who did not cooperate were arrested, and all Christians were removed from public service and from the army. A final edict ordered all Christians to make sacrifices to the pagan gods or face execution—an order that was enforced in all the eastern provinces* and in Africa, although not elsewhere in the western empire.

This oppression ended in A.D. 313, when the emperor Constantine I issued an edict promising toleration for all religions, including Christianity. He later granted Christians various privileges and strengthened the authority of church leaders. His actions marked the first steps in making Christianity the official religion of the Roman Empire. Constantine also founded the city of Constantinople in A.D. 324 and made it the new capital of his empire. In contrast to Rome, with its numerous pagan temples, Constantinople was planned as a great Christian city.

* doctrine principle, theory; or belief presented for acceptance

* theological pertaining to the nature of God, the study of religion, and religious belief

* theologian person who studies religious faith and practice

* heresy belief that is contrary to church doctrine

* excommunicate to exclude from the rites of the church

* pagan referring to a belief in more than one god; non-Christian

* edict proclamation or order that has the force of a law

* province overseas area controlled by Rome


Paul, who was both a Jew and a Roman citizen, became one of the most important leaders of the early Christian church. Once a persecutor of Christians, Paul was converted to Christianity while traveling on the road from Jerusalem to Damascus, where he reportedly saw the risen Christ. In the A.D. 40s and 50s, Paul made three long journeys through Greece and Asia Minor, bringing Christianity to those areas. His letters to his followers in Corinth, Galatia, Philippi, and Ephesus became the earliest books of the New Testament.

When Julian became emperor in A.D. 361, he attempted to reestablish pagan religion in the Roman Empire. (Julian became known as Julian the Apostate—the unfaithful one.) Christians lost their privileges, and pagan temples and institutions were revived. By that time, however, Christianity had become so widely accepted and the church had become so strong that these measures failed to extinguish the church. After Julian’s death in A.D. 363, the Christian church immediately regained its authority. In A.D. 391, the emperor Theodosius I banned all pagan religions, closed all pagan temples, and made Christianity the official religion of the empire.

In the A.D. 400s, the Roman Empire split into eastern and western parts and the Christian church became divided as well. The patriarch, or bishop of Constantinople, became the leading bishop of the Greekspeaking Eastern Church, while the bishop of Rome, called the pope, led the Western Church. By the final years of the Western Roman Empire, the Christian faith had spread beyond the empire to other peoples of Europe. However, it took centuries in the West until Christianity could establish itself in central and western Europe under the leadership of Rome. Christianity continued to play a major role in the development of Western civilization during the Middle Ages. (See also Churches and Basilicas; Religion, Roman; Rome, History of: Christian Era.)

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