By Laura Smith-Spark - CNN

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.

According to the pope's research, there is also no evidence in the Gospels that the cattle and other animals traditionally pictured gathered around the manger were actually present.

Alessandro Speciale, Vatican correspondent for the Religion News Service, told CNN the pope was not so much aiming to debunk myths as trying to show that the Jesus depicted in the Gospels is a real historical figure, who walked on earth and talked to people like anyone else.

The pope also looks at scholarly studies of the Bible, some of which have indicated for decades that the traditionally accepted birth date for Jesus is wrong, Speciale said.

See other things The Pope is challenging;