In 46 BC, Julius Caeser reformed the Roman Calendar, making December 25 the date of the winter solstice. In the northern hemisphere, this day marks the progressive increase in the length of days, and thus marks an annual celebration of light coming into the world.The astronomical solstice progressively drifted away from this date through the centuries, and the calendar we now have is adjusted so that the astronomical solstice occurs December 20-23.
There often arises a futile debate about whether the date of Christmas was modeled after “pagan” festivals of the sun. The debate is futile because the evidence is such that one can conclude whatever one wants to believe. The Emperor Aurelian declared December 25 to be the feast of Sol Invictus, the invincible sun, in 274 AD. Hippolytus of Rome may have testified to this day as the day of Christ's birth as early as 202 AD, over 70 years before the festival of Sol Invictus. For a discussion of conflicting manuscript evidence, see here.
Hippolytus didn't base his reasoning on “pagan” festivals, but he did base it on astronomy. He believed that Jesus was conceived on the same day he died, and that he died on the Passover. The Passover, of course, begins on the first full moon after the vernal equinox, and thus such belief necessarily places the birth of Jesus some nine months later on or close to the winter solstice.
(This is true of the belief of Hippolytus even if textual evidence from the Gospels may seem to contradict it as an historical fact, such as Luke's account of shepherds watching over their flocks in the fields by night, which would have been unlikely to occur in the winter.)
Surely neither the Emperor Aurelian nor Hippolytus invented the winter solstice! The Book of Malachi, which called the coming Messiah the “Sun of Righteousness,” predates them both by centuries. The Egyptians saw the sun as the emblem of Horus yet millenia earlier. To a Jew or a Christian (and many others), God created the sun to rule the day and the moon and stars to govern the night long before there were any people on earth to interpret their meaning.Debating which tradition came first seems silly to me because all of us, whether we believe in God, many gods, or no gods, agree that the sun itself predates human beings.
Whether we are celebrating the bodily incarnation of the Sun of Righteousness and Light of the World, or are celebrating the season in some radically different way, we are all living under the same sky and all bear witness to the astronomical fact that in the northern half of the earth the days will henceforth become longer and our lives will become progressively more illumined.
Even if we see neither symbolism nor divinity in the heavens above, we have the sun itself to shower its material gifts upon us. Even for those of us who grumble when the snow falls, the solstice is a promise of the warmth to come the following spring.
So I will put this my way, in hopes that each friend and reader may take of it whatever blessings she or he wishes:
Thank you all for your readership, and for contributing your questions, comments, and insights, and for your many gifts of friendship. May this season bring light and warmth into your hearts.