Some people doubt that Jesus actually existed. They claim that some first-century men made up a story, and that a bunch of people were fooled into believing it. I've heard from a lot of skeptics of Christianity, and there's a fair number who claim that Jesus never actually existed.

In this video (1:27:35), Craig Evans and Bart Ehrman debate the reliability of the gospels. These are two very highly-regarded Biblical scholars. Bart Ehrman is a well-known author and Religious Studies professor, while Craig Evans is an author and Biblical Studies professor, as well as an authority on the Dead Sea Scrolls.