Why we celebrate Christmas on December 25

A lot of people know that this goes all the way back to the Roman Empire - not surprising when you think that the Emperor Constantine made Christianity the state religion of the Emperors in the 320s AD.  But a lot of people mistakenly think that the date for Christmas was chosen to coincide with the old Roman holiday of Saturnalia, a goofy end of year celebration where slaves were given the opportunity to act as masters for a day (as long as they really didn't try to).  No, it was something different, and more important for the development of the early Church, something that grew out of one of the most difficult times in the Empire's history and came from one of their very greatest Emperors.

The third century AD was a terrible time for the Empire, with a succession of generals usurping the Imperial crown and the empire assaulted by external enemies like the great Persian king Sharpur II.  Things got so bad that the Empire split into three pieces - a "Gallic Empire" in the West comprising Britain, France, and Spain; the rich eastern provinces of Egypt and Syria falling under the domination of Queen Zenobia's oasis city state of Palmyra, and a rump Empire of Italy and Africa.  It was really possible for a moment that the Roman Empire would simply dissolve - the bonds holding it together looked too weak to hold.

A gold coin from Aurelian's reign

But the Empire was saved by emperor Aurelian, who brought the whole thing back together.  A grateful Senate awarded him the title "Restitutor Orbis" - Restorer of the World.  Mike Duncan in his great History Of Rome Podcast describes Aurelian as the Sandy Koufax of Roman Emperors - he didn't have the longest career or the most strikeouts or wins, but while he played he was simply unhittable - Left Hand Of God.  You really should listen to the first couple minutes of this podcast episode as it is Mike Duncan at his very best.

So in five short years Aurelian restored the Roman world.  But he wasn't just one of the best generals in Roman history, he was also a great statesman.  He turned his mind to why the Empire was so fragile; if he could knit it more tightly together he might be able to prevent a repeat breakup.  Aurelian believed that a big problem was that the Empire was a collection of diverse peoples - Gauls and Britons and Egyptians and Syrians who all had different cultures and beliefs.  In short, they had little in common other than the Emperor of the day and everyone had just seen how that had worked out.

And so Aurelian tried to overlay some commonality on his peoples.  Each worshiped their own local gods, but most of these religious systems were fairly flexible.  Aurelian introduced an Empire-wide cult, thinking that having some similarities would help create a common sense of Roman-ness.  Aurelian chose a cult that was popular with the Army since the closest thing that the Empire had to a single common institution throughout the Empire was the Army.

Sol Invictus was popular with the troops, the Unconquered Sun god.  Most parts of the Empire adopted this seamlessly as one of the many gods, although it seems that Aurelian seemed to believe that Sol Invictus was the only god who took many forms which were interpreted as the local deities. This was an emergent idea in the Ancient world and an expression in the chronicles say the one wax takes many moulds.

Aurelian introduced his cult on December 25, 274 AD and it became really the first Empire-wide holiday.   He succeeded in founding a common belief across the Empire, perhaps succeeded more than even he hoped.  Because the idea stuck: Emperor Constantine didn't just introduce Christianity. It's from him that we get the word Sunday, since he decreed that across the Empire the weekly day of rest would be the day of rest - the dies Solis.

And so the early Church had a challenge from a popular cult, but this was also an opportunity for them. Sol Invictus was the first half step towards monotheism and identifying Jesus Christ with the unconquered sun didn't actually turn out to be all that hard for the early Church Fathers.  Indeed, what is Easter if not the celebration of the Unconquered Son?  December 25 stuck in the calendar.  It's been celebrated all the way down through the ages - ever since 274 AD.

It wasn't the silliness of Saturnalia that had to be co-opted, it was the Feast of the Nativity of the Unconquered Son.  May tomorrow's feast day be festive indeed.  You might even want to offer a toast to Aurelian Restitutor Orbis.