If there are thirty people in a room, the chances are good that two will share a birthday. Indeed, there is less than one chance in three that this won’t happen. Double the number in the room, however, and the chances against don’t halve; rather they fall nearly to zero. By the time seventy people have arrived, the chance that no two share a birthday is one in a thousand. The “birthday problem” is good mathematical fun. Every code-breaker knows how to use this key to probability theory. It is the beginning of wisdom with regard to coincidences. That is to say, in many cases, the absence of a coincidence would be the bigger weird.
But what are the chances that just two people will share the same birthday? Pretty slim. I’d say about one in three hundred and sixty-five. (Actually, three hundred sixty-six and one quarter, but we won’t go into it.)
Now, Christmas comes but once a year, and since the beginning of the third century — at the very latest — it has come in the West on the 25th of December. The Roman Saturnalia came on the 17th of December. Note that this is not the same date. Yet I must have been told a hundred times, by people who know zilch about Christianity, or the history of much anything else, that Christmas was designed to replace the Roman Saturnalia, and was an adaptation of that old pagan festival.
One should count to eight before giving opinions on subjects one knows nothing about. (I often wish they would do this in Rome.) True, Christmas and Saturnalia both happen near the winter solstice, but neither of them on it, and anyway, so what?
Tertullian, very early in that third century, is already making fun of people who think Christians might take Saturnalia seriously. (See his De Fuga in Persecutione, published 208 AD, and you might also want to check out his Apologeticus, from a few years earlier.) He says, for instance, that the festival involves the custom of ritual bathing, and admits that he bathed on the very morning of Saturnalia. He bathes on many other mornings, too, yet as he explains, his purpose is not to honour pagan gods. It is instead to make himself clean and decent.
But here the joke turns around on itself. Tertullian also contrasts the pagan festival with Christian observances. One of his examples is holiday gift-giving. The pagans are all rushing about, acquiring presents to give one another — images come to mind of the Saturnalian shopping season in ancient Rome. He mentions that they hang wreaths, and other festive decorations; they also party and drink a lot. But not the Christians: they don’t do that. By contrast, they are habitually sacramental; not loud and lewdly materialist like those pagans. On their holy days, one finds the Christians soberly at prayer.
So here we are, eighteen centuries later, never having dreamt of turning Saturnalia into Christmas; but having, after all this time, turned Christmas into Saturnalia instead.
The better-educated wiseacre will try for a connexion between Christmas and Mithraic festivals at Alexandria. (Fat chance.) Or perhaps, the celebration of Sol Invictus, ordered by the Emperor Aurelian, which did at least fall on December 25th. But there the evidence strongly suggests the co-optation went the other way: for the Christians had taken that date before Aurelian was even born.
How had the date been selected? … Curious minds might want to know.
Joseph Ratzinger looked into this question in his (indispensible) book, The Spirit of the Liturgy. Slightly different dates were selected, East and West, for complicated reasons; but in the West, the choice was confident and consistent. This is because the date for the Annunciation had already been established (in the West) as the 25th of March — the ancient New Year, by the sighting of the vernal equinox, associated with the beginning of the world. Add exactly nine months to that, and Bob’s your uncle.
Addendum: Just annihilated the latter half of this Idlepost, which struck me in the morning light as “too much information”; sure hope nobody liked it.