Caesar's Messiah is a book and documentary by Joseph Atwill, which digs deeply into the history of the Christian and Jewish religions. Atwill's research finds that the Flavian Dynasty of Rome, in an effort to subdue a religious uprising, actually invented modern day Christianity and Rabbinical Judaism, with the help of Jewish defector Josephus.
This documentary is a great way to get acquainted with the theory and the author. In a short period of time it illustrates in great detail how the Romans may very well have invented the Jesus character in order to achieve various political and social changes.
Watch Caesar's Messiah on Amazon