These are my lecture notes from Dr. Frank A. James III's History of Christianity 1 class at Reformed Theological Seminary. The entire course and many others are available on iTunes.
Church and Roman state relations
Initially there was very little persecution of the Church as long as Christianity was perseved as a sect of Judaism. Judaism was a legal religion in the Roman empire while Christianity was not. Persecution was mainly local and sparatic, mostly as a result of mob violence. After 250 A.D. the Roman government issued an empire wide policy to persecute Christianity in order to maintain the integrity of the Roman State. The Roman leaders thought that Christians were disloyal and trying to establish a state within a state for at least three reasons:
1) The majority of Christians were unwilling to offer incense on the alter of the Roman Emperor, although almost all of the Jews were willing to do so. An alter of worship was constructed because there were some Emperors who thought of themselves as deities.
2) Christians use to get together at night in private away from the public eye, so authorities were suspicious that they were conspiring against the governing authorities.
3) Even during the day Christian meeting were somewhat secret, prompting immoral accusations against Christians. Among the accusations were those of incest (the Kiss of Peace), cannibalism, drunkenness, and orgies (Love Feasts). Slaves were taken and tortured, falsely admitting that their Christian master's were indeed involved in these accusations. Romans also misunderstood the meaning of Christian language, eating the body of Christ and drinking His blood and so on. At this time the Romans were also faced with civil unrest, plague, and famine, which made it easy for the popular idea of Christians to be bad, even blaming them for the problems of the day. They became scapegoats, so to speak.
From 33 A.D. to 64 A.D. Christians were seen as a subcomponant to Judaism, which the Romans allowed the Jews to control. Herod Agripa I executed James, the brother of John, in 44 A.D. and in 62 A.D. the Jewish high priest executed James, brother of Jesus. He was beaten and clubbed to death. Eusebias, c 263 to 339 A.D., includes these accounts and more in his work The History of the Christian Church. Tertullian, c. 160 to 220 A.D., is famously quoted as saying "the blood of the martyrs was the seed of the Church".
Roman persecution intensified from 64 A.D. to 250 A.D. Emperor Nero, who reigned from 54 to 68 A.D., was the first to openly persecute Christianity. In 64 A.D. a fire broke out in Rome and destroyed a good part of city. Rumor is that Nero started it, and in order to divert attention from himself he accused the Christians of setting the fire. Paul and Peter were killed during his reign. Nero did not persecute much outside of Rome and it only lasted 4 years, until 68 A.D. His persecution was based on a legal matter, it was a capital offense to be a Christian. He was a ruthless ruler, later he killed his mother, brother and other family members.
Next there was emperor Domitian, who reigned from 80 to 96 A.D. In 95 A.D. towards the end of his reign his government may have been attempted to be overthrown causing him to execute a reign of terror while in a state paranoia. Christians were caught in the crossfire because they most likely refused to swear loyalty to the Emperor. The Apostle John may have been exiled turning this time. Christians were not persecuted throughout the empire by decree. Emperor Tragian, who ruled c. 110 to 115 A.D. organized persecution of Christianity as a matter of policy.
