Terry,
The Christianity that ultimately prospered was the version taught by Paul, who was based at Antioch. His teachings were aligned with Hellenistic philosophy, so those teachings were more acceptable to the populace than were the strict legalistic version of the larger Jewish Christian movement under James and Peter, based at Jerusalem. These Christian groups were at odds with one another, and with other Christian sects. The Jerusalem group evolved into groups such as the Ebionites.
Paul's story was a philosophy about the impact of the Christ, whereas the Jewish Christians were practical, albeit very legalistic, and were about Jesus. The Greek and Roman philosophers had much less difficulty accepting Paul's views; they found the Jewish ritual requirements, such as circumcision, too difficult to accept.
To gain some idea of the tension between Paul's version and the Jerusalem version of Christianity, you only need read Paul's invective in his early letter, to the Galatians, and also his harsh words about the Jews' Law in Romans. You can imagine how well that went down with the Jewish Christians in Jerusalem!
In time, Paul's version gained the support of the emperors of the Eastern Roman empire, who saw political value in recognising Paul's version, and in this way they inadvertently defined Christian orthodoxy. This officially sanctioned state church determined which were the writings acceptable as their New Testament canon, and we can see their bias, as well as their inconsistencies.
Examination of the time shows why the Gentile Christians succeeded, while the message of the Jewish Christians, who were the rightful heirs, was almost obliterated.
Doug