Christianity was introduced in Rome during the 1st century AD, likely in the early to mid-40s AD. According to the New Testament, the apostle Paul wrote his Epistle to the Romans around 56-57 AD, indicating that there was already a Christian community established in Rome at that time. The early Christian community in Rome was likely made up of both Jews and Gentiles, and it faced persecution under the Roman Empire until Emperor Constantine legalized Christianity in 313 AD. After this point, Christianity became the dominant religion in Rome and throughout the Roman Empire.