Sol Invictus

In 274 CE, after his campaign against Palmyra, the emperor Aurelian dedicated a temple to Sol at Rome, endowed it richly, created a college of priests of senatorial rank, the pontifices Solis, and instituted games held every fourth year. The measure is well attested and its date is not in dispute. What it meant is.

One long-standing reading, associated above all with Gaston Halsberghe, treats the cult as an import: a Syrian solar god, taken from Emesa or from the eastern campaign, installed at Rome as a new imperial deity with an eastern character. That reading fits the timing and the plunder, and it made Sol Invictus a foreign novelty of the late empire.

A revision led by Steven Hijmans argues the opposite from the material evidence. Sol was worshipped at Rome continuously from the republic onward, holds a place in the earliest calendars, had a temple by the Circus Maximus, and appears steadily on coins and reliefs across the imperial period. On that account Aurelian elevated and reorganised an old Roman cult rather than importing a new one, and the title invictus, already used of Mithras, of Hercules and of Jupiter, is an epithet rather than a signature of origin.

The atlas records both readings and settles neither. The evidence each side leans on is largely different evidence, literary and later for the first, numismatic and archaeological for the second, which is a large part of why the disagreement has proved so durable.

Sol on the coinage is one of the commonest images of the third and early fourth centuries: a radiate figure with the right hand raised and a globe or whip in the left, over legends such as SOLI INVICTO COMITI, to the unconquered Sun, the companion. Constantine went on striking that legend for well over a decade after 312, which is the single fact that most complicates any tidy account of his conversion. Sun and emperor share attributes in this period, the radiate crown above all, and the message is less theological than political: here is a ruler who cannot be overcome.

The December date rests on one document. The Chronography of 354, a Roman almanac compiled by Furius Dionysius Filocalus, records under the eighth day before the kalends of January a natalis Invicti with thirty chariot races. The same compilation, in its list of martyrs, gives the birth of Christ on the same day. Both entries are there, and they are the earliest surviving evidence for either.

What follows from that is disputed. The older view holds that the Christian feast was placed on the pagan one to displace it. The calculation hypothesis holds that the date was reached independently, from a reckoning that put the conception at the spring equinox, and points to Christian writers using the date before Aurelian founded anything. Neither reading has carried the field, and the atlas leaves the question open rather than repeating the version that is easier to tell.