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.
Persecution was on the rise in Anatolia towards the end of the first century. 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. Towards the end of the 2nd century Tertullian wrote: "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!'"
Early Christian writers used their knowledge Hellenic language and literature to oppose Hellenocentrism. Though early Christian apologetics certainly tackled the issue of Greek religion, the criticisms of early Christian early writers also extended to what The Oxford Handbook to the Second Sophistic describes as the "cultural privilege that was deemed to accrue from the mastery of the Greek language". Tatian, a pupil of Justin Martyr, believed that Hellenic civilization was evil. He wrote about the privileged place of Attic Greek amongst the Greek dialects and mocked Greeks, comparing their minds to "the [leaky] jar of the Danaids". In a more muted polemic text called the Legatio, Athenagoras contrasts what he believes is the goodness of illiterate Christians with those who “reduce syllogisms, and clear up ambiguities, and explain etymologies".
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.