Also, just to comment on the side discussion, there's a difference between mythologies and fabrications. In a basic sense, Christianity can be 100% true and still be a mythology. At the same time, a mythology can be 100% false and still be revered in ways. The point of mythology is that it is a story—particularly one that is concerns immortal people or deeds. That doesn't mean the story is automatically true or false.
Also, I understand that Joseph Campbell is respected by many people (including George Lucas), but many of the historical bits of information the man based his opinions on were erroneous in my estimation. I don't consider him to be a very reliable scholar (though he's a good communicator and philosopher).