Augustus
…
As I’m poorly, can’t sleep and am very bored I thought I’d pass the time by posting some summaries and quotes from scholarly papers on the Christmas date. Unfortunately, as I’m poorly and haven’t slept, I can’t be bothered to make the slightest effort to be concise so no one will want to read it 
Tl;dr: there isn’t enough evidence to be certain, although, imo, one of the 2 major theories is significantly more probable than the other.
Like most ancient history, there is no objective, incontrovertible proof for how the date emerged, so we are forced to deal with probabilities. There are 2 major theories in academic scholarship though.
The Saturnalia theory that is expressed a lot on RF is not one of these as it simply doesn’t feature much in scholarly sources. This is because there is not a shred of evidence in favour of it other than they are roughly at the same time of year. It also comes from a time when Christians were still expressing hostility towards adopting pagan customs and the first recorded Christmas is only 30 years or so since Christians were being actively persecuted by Diocletian for this very reason. It’s not impossible, but that doesn’t automatically make it probable.
Also, the idea that ‘Constantine did it as a marketing ploy’ is highly unlikely as the following quote from 386 shows:
Although it is not yet the tenth year since this day became clear and familiar to us, through your zeal, it has now flourished as though it was given from the beginning many years ago. Because of this one would not be far wrong in saying that it is both new and old: new because it has only recently been made known to you, old and venerable because it has swiftly become similar in stature to days long recognised and it feels as though it is of similar age to them… This day was known from the beginning to those in the West: now it has been brought to us and before the passing of many years, has swiftly shot up, bearing such fruit as you now see – the precincts full and the church packed with the crowd who have gathered together. John Chrysostom - Homily on the date of Christmas
For Chrysostom, writing in 386 in the Eastern Roman Empire, “The West” means Rome (centre of the Western Roman Empire). As such he is acknowledging the tradition took some time to reach Constantinople from the West and only came to the Eastern part of the Empire in the 370s.
So unless we are going to operate under the assumption that Connie invented Christmas to fool the dupes on the other side of his Empire, yet forgot about fooling the dupes in his capital, ‘The City of Constantine’, it seems a bit far fetched to assume he was responsible for Christmas.
Will split this into 2 posts. The first is the slightly less inconcise version. The 2nd has a bit more detail for anyone interested.
Fwiw, all information is sourced from peer-reviewed scholarly journals or secular academic texts.
How did Christmas end up being celebrated in the middle of winter, on December 25?…
[Theories on the pagan origins of xmas are] essentially a product of the sixteenth-century Reformation, which inspired some Protestant, and in particular Calvinist, scholars to attack the historical basis of feasts like Christmas in new and pathbreaking ways. As recent research has shown, it is in the context of these early modern inquiries into the history of the liturgical year, which were often permeated by inter-confessional polemic, that the two basic approaches to understanding Christmas’s origins that continue to characterize twenty-first century debate on the subject first germinated. For lack of more appropriate labels, these two approaches may be referred to as the “History of Religions Theory” (henceforth: HRT) and the “Calculation Theory” (CT).
Roughly speaking, proponents of HRT interpret Christmas as a Christianized version or substitute for pagan celebrations that took place on the same date in the Roman calendar, the most widely cited example being the birthday of Sol Invictus on December 25.
By contrast, adherents to CT find evidence that the birthday of Christ was determined independently, by recourse to certain types of chronological speculation… Christmas on December 25 was derived from the day of Christ’s Passion, for which commemorative dates in the Julian calendar had already been established in the late-second or early-third centuries. Assuming that Christ spent a perfect number of years in the flesh, Christian scholars established a chronological parallelism between the conception in Mary’s womb (Annunciation) and his death on the cross, which were both assigned to March 25, the Roman date of the vernal equinox. In a further step, they added a schematically rounded number of nine months to the date of Jesus’ conception to arrive at his birth on the day of the winter solstice, December 25. The Origins of the Christmas Date: Some Recent Trends in Historical Research - C. P. E. Nothaft
There are a number of problems with the HRT which I won’t go into in any detail in this thread.
In short though:
1. Sol Invictus, as some new henotheistic god, didn’t actually exist. It’s just plain old Sol/Helios from before. Invictus is just an epithet attached, like adding Christ to Jesus and Sol was far from the only god to have this epithet attached to their name.
2. The idea that there was a major tradition for Sol on 25 Dec to be ‘stolen’ is highly dubious as there is no real evidence for it. It likely post-dates Christmas and may even be a response to Christmas initiated by Julian the Apostate.
3. Counterintuitively, celebrations for the ‘Unconquered Sun’ were not traditionally tied to solar events with festivities for Sol recorded on multiple dates in August and early December recorded so it is not correct to assume it must have been centred on the solstice.
We have no firm evidence for a festival for Sol on December 25th until Julian wrote his hymn to Helios in December of 362. The entry in the calendar of 354 is probably for Sol, although only the epithet invictus is used (above, n. 4), and probably dates to 354, although it was possibly added later. Circumstantial evidence suggests that a festival of Sol on the winter solstice was not yet included in such calendars in the late 320s. As the Christian celebration of Christmas on December 25th can be attested in Rome by AD 336, at which point it may already have been well-established and the celebration of Sol on that day cannot be attested before AD 354/362 and had not yet entered the calendar in the late 320s, it is impossible to postulate that Christmas arose in reaction to some solar festival. There is quite simply not one iota of explicit evidence for a major festival of Sol on December 25th prior to the establishment of Christmas, nor is there any circumstantial evidence that there was likely to have been one. There is only Julian’s overly emphatic insistence that the celebration was as old as Numa… which is a fabrication and his convoluted explanation for the date is impossible.
S Hijmans - Usener’s Christmas: A contribution to the modern construct of late antique solar syncretism)
Some more details on the Calculation Thesis follow. It should be noted though that the CT doesn’t aim to establish when people started to celebrate Christmas, but how people identified the date. There is no reason to assume that if they did establish a date that this would instantly become an important celebration, or that this was the purpose of establishing the date. Easter was the most important Christian event.
Tl;dr: there isn’t enough evidence to be certain, although, imo, one of the 2 major theories is significantly more probable than the other.
Like most ancient history, there is no objective, incontrovertible proof for how the date emerged, so we are forced to deal with probabilities. There are 2 major theories in academic scholarship though.
The Saturnalia theory that is expressed a lot on RF is not one of these as it simply doesn’t feature much in scholarly sources. This is because there is not a shred of evidence in favour of it other than they are roughly at the same time of year. It also comes from a time when Christians were still expressing hostility towards adopting pagan customs and the first recorded Christmas is only 30 years or so since Christians were being actively persecuted by Diocletian for this very reason. It’s not impossible, but that doesn’t automatically make it probable.
Also, the idea that ‘Constantine did it as a marketing ploy’ is highly unlikely as the following quote from 386 shows:
Although it is not yet the tenth year since this day became clear and familiar to us, through your zeal, it has now flourished as though it was given from the beginning many years ago. Because of this one would not be far wrong in saying that it is both new and old: new because it has only recently been made known to you, old and venerable because it has swiftly become similar in stature to days long recognised and it feels as though it is of similar age to them… This day was known from the beginning to those in the West: now it has been brought to us and before the passing of many years, has swiftly shot up, bearing such fruit as you now see – the precincts full and the church packed with the crowd who have gathered together. John Chrysostom - Homily on the date of Christmas
For Chrysostom, writing in 386 in the Eastern Roman Empire, “The West” means Rome (centre of the Western Roman Empire). As such he is acknowledging the tradition took some time to reach Constantinople from the West and only came to the Eastern part of the Empire in the 370s.
So unless we are going to operate under the assumption that Connie invented Christmas to fool the dupes on the other side of his Empire, yet forgot about fooling the dupes in his capital, ‘The City of Constantine’, it seems a bit far fetched to assume he was responsible for Christmas.
Will split this into 2 posts. The first is the slightly less inconcise version. The 2nd has a bit more detail for anyone interested.
Fwiw, all information is sourced from peer-reviewed scholarly journals or secular academic texts.
How did Christmas end up being celebrated in the middle of winter, on December 25?…
[Theories on the pagan origins of xmas are] essentially a product of the sixteenth-century Reformation, which inspired some Protestant, and in particular Calvinist, scholars to attack the historical basis of feasts like Christmas in new and pathbreaking ways. As recent research has shown, it is in the context of these early modern inquiries into the history of the liturgical year, which were often permeated by inter-confessional polemic, that the two basic approaches to understanding Christmas’s origins that continue to characterize twenty-first century debate on the subject first germinated. For lack of more appropriate labels, these two approaches may be referred to as the “History of Religions Theory” (henceforth: HRT) and the “Calculation Theory” (CT).
Roughly speaking, proponents of HRT interpret Christmas as a Christianized version or substitute for pagan celebrations that took place on the same date in the Roman calendar, the most widely cited example being the birthday of Sol Invictus on December 25.
By contrast, adherents to CT find evidence that the birthday of Christ was determined independently, by recourse to certain types of chronological speculation… Christmas on December 25 was derived from the day of Christ’s Passion, for which commemorative dates in the Julian calendar had already been established in the late-second or early-third centuries. Assuming that Christ spent a perfect number of years in the flesh, Christian scholars established a chronological parallelism between the conception in Mary’s womb (Annunciation) and his death on the cross, which were both assigned to March 25, the Roman date of the vernal equinox. In a further step, they added a schematically rounded number of nine months to the date of Jesus’ conception to arrive at his birth on the day of the winter solstice, December 25. The Origins of the Christmas Date: Some Recent Trends in Historical Research - C. P. E. Nothaft
There are a number of problems with the HRT which I won’t go into in any detail in this thread.
In short though:
1. Sol Invictus, as some new henotheistic god, didn’t actually exist. It’s just plain old Sol/Helios from before. Invictus is just an epithet attached, like adding Christ to Jesus and Sol was far from the only god to have this epithet attached to their name.
2. The idea that there was a major tradition for Sol on 25 Dec to be ‘stolen’ is highly dubious as there is no real evidence for it. It likely post-dates Christmas and may even be a response to Christmas initiated by Julian the Apostate.
3. Counterintuitively, celebrations for the ‘Unconquered Sun’ were not traditionally tied to solar events with festivities for Sol recorded on multiple dates in August and early December recorded so it is not correct to assume it must have been centred on the solstice.
We have no firm evidence for a festival for Sol on December 25th until Julian wrote his hymn to Helios in December of 362. The entry in the calendar of 354 is probably for Sol, although only the epithet invictus is used (above, n. 4), and probably dates to 354, although it was possibly added later. Circumstantial evidence suggests that a festival of Sol on the winter solstice was not yet included in such calendars in the late 320s. As the Christian celebration of Christmas on December 25th can be attested in Rome by AD 336, at which point it may already have been well-established and the celebration of Sol on that day cannot be attested before AD 354/362 and had not yet entered the calendar in the late 320s, it is impossible to postulate that Christmas arose in reaction to some solar festival. There is quite simply not one iota of explicit evidence for a major festival of Sol on December 25th prior to the establishment of Christmas, nor is there any circumstantial evidence that there was likely to have been one. There is only Julian’s overly emphatic insistence that the celebration was as old as Numa… which is a fabrication and his convoluted explanation for the date is impossible.
S Hijmans - Usener’s Christmas: A contribution to the modern construct of late antique solar syncretism)
Some more details on the Calculation Thesis follow. It should be noted though that the CT doesn’t aim to establish when people started to celebrate Christmas, but how people identified the date. There is no reason to assume that if they did establish a date that this would instantly become an important celebration, or that this was the purpose of establishing the date. Easter was the most important Christian event.
