In case you didn’t know:
It is a widely-held theory that Christians in the fourth century assigned December 25th (the Winter Solstice on the Julian calendar) as Christ’s birthday (and thus Christmas) because pagans already observed this day as a holiday. This would sidestep the problem of eliminating an already popular holiday while Christianizing the population. It is also possible to see it as early Christians replacing the Pagan celebration in an act of triumphalism. However, others claim that early Christians independently came up with the date of December 25th based on a Jewish tradition of the “integral age” of the Jewish prophets (the idea that the prophets of Israel died on the same dates as their birth or conception), and a miscalculation of the date of Jesus’ death. It is even sometimes claimed that Aurelian moved the feast of Sol Invictus to December 25th to co-opt the Christian celebration.
The Romans also practiced many traditions similar to Christmas; specifically the “Christmas tree”. The Romans often cut down evergreens and decorated them to pay homage to Saturn, the god of farming. This was to honor the fact that the evergreens remained alive during the harshness of winter. It was also traditional for Romans to exchange gifts during this holiday. These gifts were customarily made of silver, although nearly anything could be given as a gift for the occasion. Several epigrams by the poet Martial survive, seemingly crafted as riddling gift-tags for gifts of food. The medieval celebration of the Feast of Fools was another continuation of Saturnalia into the Christian era.
So Christmass is more or less a denominational holiday. :P
