At first, most Roman officials largely ignored the followers of Jesus, viewing them simply as one of the many splinter groups within Judaism, but slowly some came to oppose Christian practices and beliefs. They considered Christians to be subversive dissidents because they stopped practicing traditional rituals and they objected to the cult of the emperor. Some Romans thought that Christianity was one of the worst of the mystery cults, with immoral and indecent rituals. Pagans also feared that the Greco-Roman gods would withdraw their favor from the Roman Empire because of the Christian insistence that the pagan gods either did not exist or were evil spirits. And many worried that Christians were trying to destroy the Roman family with their insistence on a new type of kinship.

Persecutions of Christians, including torture and executions, were organized by governors of Roman provinces and sometimes by the emperor, beginning with Nero. Most persecutions were, however, local and sporadic in nature. Responses to Christianity on the part of Roman emperors varied. Some left Christians in peace, while others ordered them to sacrifice to the emperor and the Roman gods or risk death.

By the second century Christianity was changing. The belief that Jesus was soon coming again gradually waned, and as the number of converts increased, permanent institutions were established. These included buildings and a hierarchy of officials often modeled on those of the Roman Empire. Bishops, officials with jurisdiction over a certain area, became especially important. They began to assert that they had the right to determine the correct interpretation of Christian teachings and to choose their successors.

Christianity also began to attract more highly educated individuals who developed complex theological interpretations of issues that were not clear in scripture. Bishops and theologians often modified teachings that seemed upsetting to Romans, such as Jesus’s harsh words about wealth and family ties. Given all these changes, Christianity became more formal in the second century, with power more centralized.