And let's not forget about the Druids and the evergreens... Yeah, that's right. I want a war on Christmas.

History Channel - Christmas:

"In Rome, where winters were not as harsh as those in the far north, Saturnalia—a holiday in honor of Saturn, the god of agriculture—was celebrated. Beginning in the week leading up to the winter solstice and continuing for a full month, Saturnalia was a hedonistic time, when food and drink were plentiful and the normal Roman social order was turned upside down.

...Also around the time of the winter solstice, Romans observed Juvenalia, a feast honoring the children of Rome. In addition, members of the upper classes often celebrated the birthday of Mithra, the god of the unconquerable sun, on December 25. It was believed that Mithra, an infant god, was born of a rock. For some Romans, Mithra's birthday was the most sacred day of the year.

...the Bible does not mention date for his birth (a fact Puritans later pointed out in order to deny the legitimacy of the celebration). Although some evidence suggests that his birth may have occurred in the spring (why would shepherds be herding in the middle of winter?), Pope Julius I chose December 25. It is commonly believed that the church chose this date in an effort to adopt and absorb the traditions of the pagan Saturnalia festival. "