Except for this. While Jesus is a historical figure, his divinity is not based on history, but on faith. The Da Vinci Code is not "historical" either, but simply a piece of fiction a la "National Treasure."
The divinity of Jesus is based on a historical claim: that Jesus rose from the dead. Christian faith, if it means anything, is the belief that that claim is true and does not depend on how you or I "feel" about the matter. Acceptance of that claim is what distinguishes one from the Jews, from Muslims, and from the pagans. It even distinguishes Christians from Hindus, who are willing to accept Jesus' divinity (as an avatar of the divine) but not his humanity.
But the Knights Templar and the Society of Masons are real. Are you suggesting that there isn't really an invisible map on the back of the Declaration of Independence? Next you'll be trying to tell me that the Lost Ark of the Covenant is not really stored in a secret archive building in Washington DC?