Thanks for the info on the Calendar of 354, and that the games celebrated on behalf of the ‘Invictus’ would have been for Sol Invictus, Roger. I’m glad you’ve managed to clear that up. Also it’s been interesting having a look at the Calendar itself and its great illustrations.

http://www.tertullian.org/fathers/chronography_of_354_06_calendar.htm

As you will quickly see, this lists the state feasts, celebrated by games (CM=circenses missus; remember ‘panem et circenses’?). So the Natalis Invicti means a deity who could be uniquely referred to as Invictus who is a state cult. That pretty much confines us to Sol Invictus.

The unusual number of games — 30, as opposed to the 24 for the major earlier deities — again indicates a later foundation. It probably indicates the anniversary of the dedication of the temple of Sol Invictus by Aurelian, since other deities which had no defined birthday are listed with a Natalis also.

I find it hard to believe that any of the Christian emperors would institute games in honour of Sol Invictus. It is therefore much more likely that it is part of Aurelian’s creation of the cult.

The Roman aristocrat Valentinus, for whom this lavishly decorated volume was produced with the aid of a known artist, was clearly a Christian since the volume contained all these ecclesiastical documents. It also contained the portraits of ‘our emperors’, Constantius II and the ill-fated Gallus, executed later that year. (I wish I could think of a way to get colour images of the pictures)

I’m sure that you are aware of the manner in which the emperor Julian the apostate tried to borrow elements from Christianity, so the idea of a reverse borrowing is not impossible. But the actual reason for Christmas on 25 Dec. does not seem to be known. All the ancient info dates to half a century later.

It would seem from this that there’s thus no secure evidence linking Sol with the date of Christmas either. As for Invictus being a pagan festival, that’s still very much a possibility, but it could be part of the pagan revival that was beginning to take shape after the legalisation of Christianity, and could be the result of a conscious, but unofficial, pagan borrowing for a pagan cult from Christianity.

I don’t know if any of that makes sense to you. I’d certainly appreciate hearing your comments on the above possible scenario.

I would hypothesis confusion between Sol Invictus and Mithras, since the dies natalis solis invicti is documented in the Chronography of 354 (and there only, apparently). This is of course later than the celebration of Christmas, recorded in the Chronography. However it is hard to believe that the dies was instituted by any of the Christian emperors.

I intend to do a bit more about Mithras – specifically, examining the claim that the date of Christmas Day – December 25th – was taken from the cult of Mithras. This claim has been around for over a century, but the evidence for it is actually much weaker than it appears. In fact, it looks like it could well be the other way on – that December 25th was originally a Christian holy day, commemorating our Lord’s birth, but that 19th century scholarship confused the description of the festival from the late Roman sources to produce a false claim that it was originally the holy day of a Roman god.