I though the following points were very interesting.
The development of the Jesus Christ story is best explained not as simply a "paganization" of Judaism, but as a part of Jewish literary tradition. What did set Christianity apart, however, was its crossover status into non-Jewish communities, where Jewish literary traditions were not understood. A combination of factors then led to its growing acceptance. The destruction of Judea left many diaspora Jews in despair and without a grounding for traditional Judaism, so the story of Jesus had appeal to them. Unlike most of the Greek and Roman religions, Christianity was highly evangelical with its claims of salvation and "truth". People living in the Roman Empire had grown up with messages of confidence and strength, but in the 3rd and 4th centuries Rome went through a series of hardships so the Christian story of suffering, redemption, and humility, rooted in the history of Jewish hardships, appealed to a people who were surrounded by religions based on a culture of superiority that was now failing. For those who looked deeper into the religion, many were impressed with the degree to which the life of Jesus seemed to have been so completely foretold by the earlier Hebrew scriptures. The numerous parallels between the Gospels and the "Old Testament" convinced many that the religion "had to be true", how else could one account for so many "fulfilled prophecies"? They declined to understand, however, that the parallels are there because the Gospels are made-up stories based on the Hebrew scriptures. As Christians began filling the ranks of the military in the 4th century Constantine and other emperors had reasons to cater to the religion, and they found that people who were willing to die to spread their religion to new lands made for good soldiers.