Why did the Romans try to stop the spread of Christianity?

The Romans did not try to stop the spread of Christianity. There were alternations between periods of toleration and periods of persecution. Some Roman emperors thought that Christianity was a threat to the Roman state because many bureaucrats and soldiers converted to Christianity. The Romans saw their state as being interlinked with Roman Religion. The persecutions were aimed mainly at the civil service and the Christian clergy, rather than Christianity as such. The last and worse persecution, the Great Persecution, failed because it was difficult to implement, because of the resistance of the Christians and because it undermined the stability of the empire. After that, the emperors endorsed Christianity, favored it over other religions and promoted it. Eventually, Christianity became the state religion of the empire. With imperial support, the spread of Christianity accelerated.