Paul

The man known to us as the Apostle Paul is described to us first in the New Testament as Saul of Tarsus in the book of Acts. Here he is found in hearty agreement with those who stone Stephen to death. Later, while on a mission to Damascus in search of more followers of "the Way" to capture and imprison, Saul encounters a vision of the man Jesus of Nazareth, whose disciples he is persecuting; and hereafter he himself becomes a follower of Jesus. Saul's name is changed to Paul and he becomes the person, perhaps more than any other in history, responsible for what the religion of Christianity will become. His influence is considered so profound it is perhaps inestimable.

Part of this influence is also seen by some scholars as holding the Apostle Paul, perhaps almost as much as Jesus and his teachings, responsible for the parting of the ways between 1st century Judaism and the Jewish/Christianity of "the Way." For more evidence of this reasoning, see for one example: Stuhlmacher UCPS1992.