Though Jesus' birth is celebrated on December 25, most scholars agree that it is unlikely he was actually born on this date. The choice of December 25 for the Church's celebration of the Nativity is most likely to have been in order to squelch attendance at pagan solstice festivals falling on the same day.
This article would seem to contradict that....
Time was when I, like most people, took it for granted the winter solstice and, in particular, the Roman Feast of the Birth of the Unconquered Sun were simply pagan celebrations that hung around into Christian times. In fact, when I set out to write this book I still thought this. But I discovered the reality is far more complicated and interesting. Indeed, it turns out this widely assumed "fact" that "everybody knows" is probably another sample of pseudo-knowledge. For according to William Tighe, a church history specialist at Pennsylvania's Muhlenberg College, "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."