William Tighe, who is a historian and a member of the board of the Anglicanorum Coetibus Society, has an article in Touchstone Magazine that disputes the popular idea that Christians co-opted a pagan festival by making Christmas happen on Dec. 25.
In fact, he argues it is the reverse:
Many Christians think that Christians celebrate Christ’s birth on December 25th because the church fathers appropriated the date of a pagan festival. Almost no one minds, except for a few groups on the fringes of American Evangelicalism, who seem to think that this makes Christmas itself a pagan festival. But it is perhaps interesting to know that the choice of December 25th is the result of attempts among the earliest Christians to figure out the date of Jesus’ birth based on calendrical calculations that had nothing to do with pagan festivals.
Rather, the pagan festival of the “Birth of the Unconquered Sun” instituted by the Roman Emperor Aurelian on 25 December 274, was almost certainly an attempt to create a pagan alternative to a date that was already of some significance to Roman Christians. Thus the “pagan origins of Christmas” is a myth without historical substance.
For his arguments, head on over to Touchstone Magazine for the full article.