On this day we in the Western world celebrate the birth of a Middle Eastern man who would grow up to become a radical Jewish prophet, who would be executed by the Romans for sedition, and around whom people would create a brand new religion. Within a few centuries, this religion would became the official state religion of the Roman Empire.
We don’t actually know the date of his birth, but as Alexander the Great had demonstrated, religious syncretism works well. It made sense then for early Roman rulers, with the Empire scattered to the far reaches of Europe, to co-opt pagan Winter Solstice celebrations and declare the birthday of their state religion’s founder as being at roughly the same time as these existing celebrations.
Religious syncretism means you don’t change the date. You don’t change the rituals. You just slip your own purpose right alongside what’s already there and ride that joyous celebratory wave!
So enjoy the day and have a Merry Christmas everyone!