Why Is Christmas on December 25?

Part 2: The Sol Invictus Factoids

Author: K. R. Harriman

Greek Silver Kylix Depicting Helios and a Chariot. Found in Panticapaeum, first half of the 3rd century BC (H`ermitage Museum, St. Petersburg)

The celebration of Sol Invictus has received more support as the precedent for Christmas on the scholarly level than it seems to have received on the popular level. The story goes that the Roman emperor Aurelian instituted the festival on December 25 in 274 to be celebrated on that day thereafter. The problem with this particular statement is — you guessed it — there is no direct evidence for this institution in association with this day. I have tried to find the source of the claim that Aurliean instituted a celebration of the god Sol on December 25, 274. For all the traction this factoid has — for it indeed merely resembles a fact in how often it is assumed and repeated — you would think there would be either ample evidence or at least one explicit reference. But in none of the primary histories of Aurelian is there any mention of this date (whether as the winter solstice [by the Julian calendar], the twenty-fifth day of the twelfth month, eight days before the Kalends of January, or any other name of December 25). It is not in Aurelius Victor (Epitome de Caesaribus 35), Eutropius (Abridgement of Roman History 9.13–15), Zosimus (New History Book 1), or the Historia Augusta (“Life of Aurelian”). It is on no coin. It is featured in no inscription.

Aurelian did establish a quadrennial festival and dedicate a temple for the sun god in 274, but not of a distinct deity known as Sol Invictus (Hijmans, “Sol Invictus, the Winter Solstice, and the Origins of Christmas”; hereafter in this section I draw chiefly from Hijmans’s work). More importantly, let us review the evidence for this association of a festival of Sol Invictus with December 25:

1) A document known as the Calendar/Chronography of 354 refers (in abbreviated form) to a festival of Natalis Invicti (the Birth of Invictus), celebrated with thirty chariot races.

2) Julian the Apostate’s hymn to King Helios, which refers to the festival of Sol Invictus as being between Saturnalia and the new year.

3) An anti-catholic gloss of the twelfth-century Syriac scholar Jacob Bar Salibi.

4) An anonymous, undated homily that relates the conceptions and births of Jesus and John the Baptist to the equinoxes and solstices, wherein Jesus’s birth falls on the winter solstice (December 25 in the Julian calendar).

5) An undated Egyptian calendar that refers to the birthday of the sun and increase of the light on December 25, but not to any festivals. (Hijmans, “Usener’s Christmas,” 142–44)

Frankly, this list of evidence is remarkably weak for how taken-for-granted this precedent of a Sol Invictus festival on December 25 is. I will review these in reverse order, as presumptive readings of the first two are the ultimate sources for the claims about Aurelian’s festival for Sol Invictus.

Fra Angelico: Nativity. Fresco in San Marco Convent, cell. no. 5, Firenze Italy. ca. 1440.

The Egyptian calendar is of no particular use because all it can tell us is that this date was in some way associated with the winter solstice, but not with any festival of a sun deity. I mention it for the sake of completeness, not because there is anything especially indicative about it one way or the other for this debate. The homily — succinctly and directly titled On the Solstices and Equinoxes of the Conception and Birth of our Lord Jesus Christ and John the Baptist — is more interesting because I think its argument does exemplify the chronological arguments and correlations that some early Christians engaged in (more on this later). But what tends to draw more attention is a single statement by the author — in the midst of this long argument — that some pagans may say that December 25 is the birthday of the sun, to which Christians should respond that Christ is the true sun. Much like the Egyptian calendar, this does not indicate a festival that the author is responding to, but a simple note about the association of the winter solstice with the subsequent increase in sunlight. In any case, since the date and provenance are quite difficult to ascertain (though it is often posited as being a fourth-century document), it is unclear if what we see in this document is a presentation of the reasoning behind the date or if, as Nothaft insinuates, it “merely offers a post-hoc rationalization of a date that had been originally chosen for different reasons” (“Origins,” 905).

The value of the gloss by a scholiast in the work of Jacob Bar-Salibi should be readily apparent. Whether it was added soon or long after the original date of writing, it is far too late to be of any real value in determining why the early Christians chose December 25. What is significant is how it demonstrates a history of rhetoric that would give rise to the HRT. Bar-Salibi claimed that Christmas was on December 25, but the person glossing his work disagreed because he thought January 6 was Jesus’s birthday. To explain why others, including Bar-Salibi, thought that the date was December 25, the scholiast claimed that “it is said” that the early Christians did this to supplant a feast day for the rising of the sun (Hijmans, “Sol Invictus,” 379, 396). Although this statement is less ambiguous than the previous two pieces of evidence, its lateness combined with its obvious polemical purpose undermine its value. It could only serve as circumstantial confirmation of the reasoning if its claims about a festival supplanted by Christmas could be established on other grounds.

Emperor Julian, called the Apostate. Roman statue in Musee de Cluny et Montmarte, France.

Next, we have Julian the Apostate’s Hymn to King Helios (= Oration 4). Julian was Emperor of the West from 361–363 and therefore postdates what is perhaps our earliest evidence for the actual celebration of Christmas, but he is sometimes treated as a valuable source for what he says about the festival and its history. His own festival he refers to as one commemorated with annual sacrifices (Loeb Classical Library, Orations 131D), in contrast with the quadrennial games instituted relatively recently (i.e., eighty-eight years before this hymn by Aurelian; Orations 155B). This latter celebration is clearly distinct from the ritual that he connects to Numa — the legendary second king of Rome after Romulus — of celebrating the invincible sun after Saturnalia but before the New Year (Orations 155A–156D). Even if we grant Julian’s accuracy in his latter statement about the celebration of Sol/Helios, he is clearly distinguishing that festival from Aurelian’s quadrennial games. The ritual of his time may have been an observance of the solstice in light of his devotion to the sun god and desire to renew pre-Christian Roman traditions and values (including said devotion), but his statements can hardly be seen as evidentially strong support for a pre-Christian festival dedicated to Sol Invictus on December 25.

Finally, we have the Calendar/Chronography of 354 (sometimes also referred to as the Philocalian calendar). This document is the true keystone in the case for a festival of Sol Invictus taken over by the Christians, since it is our earliest testimony to a festival celebrating the birth of Invictus (N[atalis] Invicti). The calendar was also accompanied by a register of martyrs, headed by Jesus and with reference made to his birth on December 25 (the eighth day before the Kalends of January). However, this register seems to go back to a list made originally in 336 and thus it seems that 336 is the latest possible date for the celebration of Christmas by the Christians (most recent analyses note this point in abbreviated form, for a fuller account of the reasoning, see Martin Wallraff, Christus Verus Sol, 179–82). Of course, since this year is only the terminus ad quem, it is likely that the celebration on this day predates this source.

Francesco di Giorgio Martini, Pinacoteca Nazionale, Siena, 1475.

What then of this birthday of Invictus? Scholars have tended to assume that this is a reference to Sol Invictus and have thus concluded that this is evidence for the celebration of the birth of Sol Invictus on December 25. This conclusion is by no means warranted for three reasons. First, unlike Christ for Jesus, Invictus was not a distinct honorific for Sol to the point that it could function as a shorthand name. Before, during, and after the late third century to mid-fourth century time period that concerns us here, Invictus was an epithet used for many figures, including the emperors, Hercules, Jupiter, and Mars. It was not even the case that Invictus applied most often to Sol, as is demonstrable from numismatic (coins) and inscriptional evidence, and there are a multitude of references to Sol without the use of the epithet (Hijmans, “Usener’s Christmas,” 140 n. 4).

Second, outside of Julian’s claims, the evidence we have for festivals dedicated to Sol puts the date all over the place, but never at December 25. In fact, in the same document it refers to a festival of Sol in October beginning on the 19th and ending on the 22nd as well as another festival on August 28. The former date is most likely in reference to the games of Aurelian, since this year would be one in which they would have been observed (eighty years after the institution) and we do not have other evidence indicating the date of Aurelian’s festival. Other sources refer to festivals of Sol on August 8/9, August 28, and December 11, none of which are astronomically significant dates (Ibid., 148–50; “Sol Invictus,” 384–86). This is why the popular story of Aurelian’s institution of a festival of Sol Invictus does not work. When we combine this evidence with Julian’s statements, it is clear that Aurelian’s quadrennial festival could not have been on December 25, much less could it have given rise to an annual festival on that day by the Christians. And lest we forget, our earliest evidence for an established festival for the birthday of Invictus — even if it is Sol Invictus — postdates the latest possible date for an established festival for the birthday of Jesus. Even on the reading most generous to the HRT, we do not have conclusive evidence here for a well-established pre-existing festival of Sol Invictus prior to the Christian celebration of Christmas that the Christians appropriated and supplanted. But even that is not the whole story here.

Third, there seem to be textual problems with this reference to the birthday of Invictus on December 25. It seems that this reference to Natalis Invicti could be a later addition to this calendar of 354, given that it does not directly identify the deity or emperor of dedication and its number of chariot races (a practice standardized in Constantine’s reign to avoid sacrifices) is not a multiple of twelve like in the other cases in this calendar (Hijmans, “Usener’s Christmas,” 150–51). It is thus possible that even this reference is not the earliest one to a Roman festival on December 25 if it was added more than eight years later.

In short, we have no clear evidence that a festival dedicated to Sol Invictus was celebrated on December 25 prior to the Christian celebration of Christmas on that date. More importantly, we do not have any evidence that such a pre-existing festival presented the impetus for celebrating Jesus’s birth on this day. The popularity of this assertion and various sub-assertions around it (such as its institution by Aurelian) is not commensurate with its evidential basis.

Nativity (Orthodox Icon)

Before I move on, I want to address a couple other myths that have developed about the origin of Christmas. No, there is no evidence that Constantine decreed this date for Christmas as a merging of his own piety towards a sun cult and his elevation of Christianity. As Nothaft notes, this is even more inexplicable in light of the fact that Constantinople did not celebrate Christmas on the December 25 until approximately 380, long after Constantine’s death (“Origins,” 906). This is demonstrable from a homily by John Chrysostom given in Antioch in 386 (Homily on the Day of the Birth of Our Savior Jesus Christ 1), wherein he mentions that it has not been ten years since they have celebrated Jesus’s birth on December 25, but that it had been celebrated in the West long before that time. His statement that those in the West knew of this date “from the beginning” is likely hyperbole, but it nevertheless shows that the date had by that point become well established in the West in contrast to the East, where the date had most often been seen as January 6.

Likewise, the tale that gets passed around about Liberius, the bishop of Rome, issuing a decree in 354 establishing this practice is just that: a mere tale. It has no grounding in history, nor can anyone point to an actual decree, hence why no citation ever accompanies this claim. Such a text exists only in the hypothesis of Hermann Usener, who wrote about the matter in the late nineteenth and early twentieth centuries (for this particular claim, see his Religionsgeschichtliche Untersuchungen, 270–74). Usener seems to have combined a reference to Liberius’s Nativity sermon by Ambrose (On Virginity 3.1) with some kind of instituting decree that neither he nor anyone else can cite independently.

The question then remains: Why did the early Christians choose December 25? To answer this question, I want to do two things. First, I want to close off one path taken by some apologists that looks like a dead end. Second, I want to examine what the patristic authors who actually wrote about this stuff say.

Primary Sources:

Secondary Sources:

  • Hijmans, Steven. “Sol Invictus, the Winter Solstice, and the Origins of Christmas.” Mouseion [Series 3] 3 (2003): 377–98. (available online on academia.edu)
  • Hijmans, Steven. “Usener’s Christmas: A Contribution to the Modern Construct of Late Antique Solar Syncretism.” Pages 139–52 in Hermann Usener und die Metamorphosen der Philologie. Edited by M. Espagne and P. Rabault-Feuerhahn. Wiesbaden: Harrassowitz, 2011. (available online on academia.edu)
  • Nothaft, Carl Philipp Emanuel. “The Origins of the Christmas Date: Some Recent Trends in Historical Research.” Church History 81 (2012): 903–11.
  • Usener, Hermann. Religionsgeschichtliche Untersuchungen. Vol. 1: Das Weihnachtsfest. Bonn: Cohen & Son, 1889.
  • Wallraff, Martin. Christus Verus Sol: Sonnenverehung und Christentum in der Spätantike. Jahrbuch für Antike und Christentum Ergänzungsband 32. Münster: Aschendorffsche, 2001.
  • Also see ch. 9 of Hijmans’s dissertation, available at https://www.rug.nl/research/portal/en/publications/sol(af334f2a-d157-4793-95c6-80d2f6323668).html.

Read all 5 installments in K. R. Harrimans excellent series:



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