Contrary to what you’ll read all over the internet, Christians did not steal December 25 from pagans as the day to celebrate Christmas. Ancient data show it was the other way around. Listen and find out why. Here’s a hint: you have to understand that the effort to calculate the birth of Jesus spun off the early church obsession with calculating the days of the crucifixion and resurrection. That all took place long before the time of Aurelian, who is the reference point for the argument that the date is pagan. It also pre-dates the celebration of the birth of Jesus. Early Christians really didn’t care too much about that initially, though there was a lot of discussion about when it happened. The issue is that two dates (December 25 and January 6) were the two major candidates, and there is evidence of both being discussed by early Christians long before Aurelian’s time.
Source: Naked Bible Podcast