The thing about the celebration of Christmas is that there is several events in the Christmas Story that are wrapped up into a one day event for convenience when in reality they are events that happen over several months before the Dec 25th 2 B.C. The birth of Christ didn't happen on Dec 25, I don't think any one really knows when he was born, but historical we do know when the wise men saw the star that lead them to Jesus. Again I'm not up on the details, one needs to do a internet search for the details. There was an advertisement for a Video or book on the web site and I think the advertisement was for Rick Larson DVD called "The Star of Bethlehem: Unlock the Mystery of the World's Most Famous Star" In that DVD he deals with the wise men and the star and a few other things and when they all happened historically. Do a search on him and his work on the Internet.
And that advertisement is for Rick Larson DVD, "The Star of Bethlehem: Unlock the Mystery of the World's Most Famous Star." in which he talks about where the Dec 25th date comes from. In fact it is the only advertisement I see on the site.