Christianity arose around the year 100 ad. In this epoch were the Romans the boss in Palestine. This is the land where Jesus Christ was born in the year 0. The Romans were always been very religious. But their faith did not seem very much like Christianity. It seemed more like the religion that the ancient Greeks also had had. They believed in multiple gods. This is called polytheism.
The Roman religion was the State religion. That meant that everyone had to practice this religion. Starting from the year 42 BC, this meant that the emperor. In the year 42 BC: Julius Caesar deified. This meant that he was a temple and priests were given that worshipped him. Two years after his death he was thus seen as a god. That was pretty normal for this epoch.
In the year 44 BC he was killed because the Senate thought he would be King. This would mean that the Senate would lose its power to Julius Caesar. But Caesar was in his test amant very generous towards the city and its inhabitants. Caesar's gardens were given to the city and every citizen got 10 weeks pay. A good friend of Caesar told the citizens who were the assassins of Caesar. The citizens burned the houses of the killers. Now the friend of Julius Caesar the boss of Rome. This friend was called Marcus Antonius. In the year 27 BC Mark Antony left all his possessions after to August. Augustus was the first emperor in the history. He ruled until the year 14 ad.
Also Augustus was deified after his death. And as mentioned, all inhabitants of the Roman Empire the Emperor worship. The Roman religion was the State religion. But this was a problem for the many Jews who lived in the East of the Empire. They were allowed to by their faith only their own God to worship. Starting from the year 100 a.d., there were also more and more Christians. They had the same problem. They too were allowed to no one besides their own God to worship. This was the reason the Romans persecuted the Jews and Christians.
The Christians were the fault of all disasters that the Roman Empire encountered. The persecution lasted until the second century. In the second century said Emperor Trajan that the Christians had to be left alone. They were no longer actively persecuted. Yet the Romans remained Christians and Jews see as a danger to society. Christianity was also still banned.
Emperor Constantine changed it. He drew the ban on Christianity in 312. In the year he had 312 a war won because he had prayed to the God of the Christians. However, it took a long time before the new State religion was Christianity. Only in 394 made Emperor Theodotius of Christianity the State religion. In the history of Christianity, this was a big step. It meant that they were now changed by a forbidden religion in the only permitted religion.