Religion in the Roman Empire
The official Roman religion was the worship of a large group of Greco Roman gods such a Jupiter, Juno, Minerva and Mars. A Roman priest was responsible for the proper ritual worship to the gods. The very success of the Roman Empire proved that the Romans had properly worshiped their gods.
The Romans were tolerant of other peoples' gods, allowing natives in their provinces to worship whatever gods they chose. Beyond the official gods, individual families and regions had their local gods.
In 63 BC the Romans became the indirect rulers of Judea. There the Romans found themselves often drawn into the divisions between various Jewish groups. It was the Roman involvement in the divisions caused by Jesus of Nazareth that would change the world. Jesus was a Jew who preached for greater fulfillment of the words of Jewish prophets. The Romans considered Jesus a threat to their rule and had him crucified. His followers believed that he was resurrected.
Initially, Christianity which the group became known after the Christo, the anointed one, was considered just another sect within Judaism. Paul of Taurus considered by many as the second founder of Christianity. He believed that the word of Jesus should be spread not only to Jews but to all. Paul taught that Christ was the son of God and by accepting Christ as their savior people could be saved.
Christianity spread steadily through the empire. By the year 100, there were 100 churches in the Empire. Initially, the Romans paid little attention to Christianities advances. At some point, however, Christians who refused to participate in Roman public ceremonies to the gods were considered a threat to the empire. There followed a period of intermittent repressions of the Christians especially during Nero's time. Christianity however, continued to strengthen gaining support throughout the Empire. Constantine became the first Christian Emperor. Under Theodosius who ruled from 378-395, it became the official religion of the Roman Empire.