It's Christmas, but not as you know it: a new book released this week by Pope Benedict XVI looks at the early life of Jesus -- and debunks several myths about how the Nativity unfolded.

In "Jesus of Nazareth -- The Infancy Narratives," the pope says the Christian calendar is actually based on a blunder by a sixth century monk, who Benedict says was several years off in his calculation of Jesus' birth date.

Even the Pope is trying to debunk the GOP myths.