The earliest followers of Jesus composed an apocalyptic, Second Temple Jewish sect, which historians refer to as Jewish Christianity. The first part of the period, during the lifetimes of the Twelve Apostles, is called the Apostolic Age. In line with the Great Commission attributed to the resurrected Jesus, the Apostles are said to have dispersed from Jerusalem, and the Christian missionary activity spread Christianity to cities throughout the Hellenistic world and even beyond the Roman Empire. The relationship of Paul the Apostle and Judaism is still disputed although Paul's influence on Christian thinking is said to be more significant than any other New Testament author.
Early Christians suffered under sporadic anti-Christian policies in the Roman Empire as the result of local pagan populations putting pressure on the imperial authorities to take action against the Christians in their midst, who were thought to bring misfortune by their refusal to honour the gods.
As the existence of the Christians became more widely known, it became increasingly clear that they were (a) antisocial, in that they did not participate in the normal social life of their communities; (b) sacrilegious, in that they refused to worship the gods; and (c) dangerous, in that the gods did not take kindly to communities that harbored those who failed to offer them cult. By the end of the second century, the Christian apologist (literally, 'defender' of the faith) Tertullian complained about the widespread perception that Christians were the source of all disasters brought against the human race by the gods. 'They think the Christians the cause of every public disaster, of every affliction with which the people are visited. If the Tiber rises as high as the city walls, if the Nile does not send its waters up over the fields, if the heavens give no rain, if there is an earthquake, if there is famine or pestilence, straightway the cry is, "Away with the Christians to the lion!"
Persecution was on the rise in Anatolia towards the end of the first century, and in 111, emperor Trajan issued regulations about the conduct of trials of Christians under the Roman governor of the area. The first action taken against Christians by the order of an emperor occurred half a century earlier under Nero after the Great Fire of Rome in 64 AD.
During the Ante-Nicene Period following the Apostolic Age, a great diversity of views emerged simultaneously with strong unifying characteristics lacking in the apostolic period. Part of the unifying trend was an increasingly harsh anti-Judaism and rejection of Judaizers. Early Christianity gradually grew apart from Judaism during the first two centuries and established itself as a predominantly gentile religion in the Roman Empire.
According to Will Durant, the Christian Church prevailed over paganism because it offered a much more attractive doctrine and because the church leaders addressed human needs better than their rivals.