Yeah he was born in the lambing season - not December. The Church basically said to a bunch of Pagans partying it up that they could keep partying as long as they partied about Jesus - it was a compromise that stuck.
I love theories like that. We resurrected dinosaurs but they went on a rampage, destroying civilization. Eventually, they were domesticated but so much of it was lost, we had to start over.
look it up.