The emergence of Christianity has its roots in the Middle Eastern religion of Judaism. Judaic theology teaches of a messiah that will deliver followers from sin and into heaven. A man by the name of Jesus claimed to be the messiah of the Jews and his followers communicated this message after his execution. There were a variety of reasons that Jews accepted the message of Jesus as messiah and converted to the fledgling religion.
Many Jews had grown tired of the rigidity of Judaic doctrine. They felt a great distance between themselves and God. There was also a certain elitism that Jewish leadership demonstrated and this created distance between the faithful and their leaders. Christianity and the message of Jesus also offered optimism and hope for salvation after death. This optimism especially appealed to poor and destitute of society.
An important early missionary of the Christian church was Paul. Paul was a Jew that was very well educated and actually lived in Rome earlier in his life. Paul believed that new Christians did not have to be Jewish first. He made vast efforts to convert Gentiles (non-Jews) to Christianity. He could speak Greek and Latin and understood what motivated members of different cultures. Paul was able to establish a foothold in the vast Roman empire.
The spread of Christianity to Rome was a very important development because of the vastness of the empire. At its height, Rome held dominion over fifty million people. The acceptance of the new religion in the empire would make Christianity among the most practiced religions in the world.
Roman authorities did not embrace Christianity in the early years. In fact, Romans persecuted and killed Christians in large numbers. This martyrdom did not actually stop the spread Christianity, and may have evened hastened its spread.
Two emperors of Rome were important in the emergence of Christianity as a world religion. Constantine the Great, in 313 AD, made it legal to practice Christianity, and was a convert himself. Constantine moved the capital east to Asia minor, and spread Christianity to Greek speaking people in the region. A second emperor, Theodosius declared Christianity the official religion of the state and actually subjugated his authority to the Roman church. These two emperors were important to the development of Christianity as a political and cultural force in the Western world.