It was always known that in the mid fourth century bishops of the Roman Church began celebrating Jesus birth on December 25th to draw attention away from SEVERAL mystery cult religions that had festivals at this time.
The most popular was actually that of Mithraism. But also the winter solstice was celebrated on that day and the feast of Sarturnalia. The bishops attempted to put focus on a Christian theme like the birth of Christ even though they knew that the date was probably between April - September no one can pin it down exactly. Clement thought it was May 20. January 6th was considered the day of Jesus Baptism and so the eastern church celebrates Christmas on Jan 6 as a result.
Don't put too much emphasis on Saturnalia as the reason because it was actually Mithraism that was competing with the Church at the time and was similar to the masons of our day in that some Christians were getting involved for the sake of benefits of the secret society aspects. One of the most popular aspects of Mithraic worship was the feast day of the god Mithras which fell on Dec 25. On this day they brought gifts.
I just happened to be reading this in my class on New Testament Survey from one of the text books "Exploring the New Testament World - An Illustrated Guide to the World of Jesus and the First Christians" by Albert A. Bell Jr.
So the fact that they were attempting to replace these pagan feasts which were so popular with the masses with a Christian Themed Holiday was known then and throughout history for anyone who is willing to read history.
The question then arises "Was that a good idea?" Well it did eventually replace the feast of Mithras and the feast of Saturnalia so it seems to have worked out well in that regards.
It make no sense to suggest that celebrating Christmas is an attempt to worship pagan gods because that is a reversal of the history that occurred and you can't change history whether you want to our not.
If you discover someone trying to replace the celebration of Christ birth on Dec 25th with the worship of Mithra and the accompanying rituals that went along with Mirthraism then that would be someone who is trying to return to those feasts that the bishops were trying to replace. I am sure they are out there somewhere.
Claiming that celebrating Christ's birth on Dec 25 is pagan because they used to have pagan feasts on that day is flawed logic. That was the whole point of celebrating Christ's birth on that day, to replace and get rid of the pagan festivals. If they chose another day the pagan festivals would have still been observed but instead they faded off the stage of history.
Now technically Jesus never said to celebrate his birthday on any day of the year so there is no compelling reason to feel that you should. But there is also no reason to call Christmas a pagan celebration because it is not. It is more like a man made religious holiday based on a Christian Theme.
It's a little early for this thread.
I figured we would be talking about the history of Halloween first.