Why We Celebrate Christmas on December 25th
The history is more complex than many realize
In ten days, Western Christians will gather to celebrate the birth of Jesus Christ on December 25th. But why this day? What is it about this day—in the dark of winter—that made people decide, this is the day we should celebrate Jesus’s birth?
The internet loves the rumor that December 25th was a pagan holiday taken over by the church, but new research is casting doubt on that. The truth may actually be shrouded in mystery.
This mystery exists because the Bible doesn’t tell us when Jesus was born (and even if it did, the stories of Jesus birth are most likely made up anyway). Nor do any of our non-Biblical sources for information about Jesus give us any clues to when he might have been born.
The earliest (non) celebrations
To the earliest Christians, the date of Jesus’s birth was not of much concern or interest. The first Christians were likely more concerned with the date of Jesus’s supposed return; not to mention, the early Church fathers expressed disapproval of birthday celebrations in general.1
It was not until around 200 CE that Christians began showing any interest at all in calculating Jesus's birthday. That’s when Clement of Alexandria reports the first, various attempts being made to determine the date.
He writes that some thought Jesus was born in May, others in April, and still others in January. One group called the Basilidians were actually celebrating Jesus's baptism on January 10th or 6th, as they believed this was when Jesus became the Son of God.2
The earliest widespread celebration of Jesus's birth emerged in Egypt not on December 25th, but on January 6th—in a festival called Epiphany ("manifestation") or Theophany ("appearance of God"). The origins of this date are murky. Scholars once thought it was connected to an ancient Egyptian winter solstice celebration, but this theory has been largely debunked.3
What we do know is that by the fourth century, Christians throughout the eastern Mediterranean were celebrating January 6th as a feast marking both Jesus's birth and baptism. In Syria, we have evidence from Ephrem's hymns that this celebration also incorporated the visit of the Magi and Jesus's first miracle at Cana.4
This rich January celebration would continue until the western date of December 25th gradually began to take precedence.
The emergence of December 25th
Rome did things differently. The first clear evidence we have for December 25th comes from what's called the Philocalian Calendar of 354 CE, though scholars believe the celebration started around 336 CE. It’s unclear, however, how this date became associated with the birth of Jesus, though two main hypotheses have emerged over the years.
For years, many historians believed Christians chose December 25th to compete with the Roman festival of Sol Invictus ("The Unconquered Sun"), which Emperor Aurelian established in 274 CE.
However, recent scholarship has turned this theory on its head. In 2003, researcher Steven Hijmans showed that the evidence for a Sol Invictus festival on December 25th is actually very thin. He argues the first person to claim Christians copied December 25th from pagans was a Roman Emperor who rejected Christianity and was actively working to restore pagan worship throughout the empire.5
In other words, the idea that Christians deliberately chose December 25th to override a pagan holiday—a theory many people take for granted today—may have originally been anti-Christian propaganda rather than historical fact.
The other major theory (called the "Calculation hypothesis") suggests early Christians used an interesting bit of symbolic mathematics to “calculate” Jesus’s birthday.
They believed great prophets died on the same date they were conceived. Since many early Christians calculated Jesus's death as March 25th (sometime around Passover, that date is also contested), they reasoned this must also have been the date of his conception. Count forward nine months, and you arrive at December 25th for his birth.
The short answer is that we really don’t know why we celebrate Christmas on December 25th.
The spread of December 25th
What we do know is that the spread of December 25th as Christmas was surprisingly slow. When John Chrysostom preached about it in Antioch in 386 CE, he said it had been celebrated there for less than ten years.6
Jerusalem and Egypt didn't adopt December 25th until well into the 5th century. The Armenian Church (and many churches in the East) never adopted it at all— they still celebrate Jesus's birth on January 6th!
The fact of the matter is that the the early church didn't see Christmas as being nearly as important as we do today. St. Augustine, writing around 400 CE, considered Christmas a mere "commemoration" (memoria), while Easter was a true "sacrament" (sacramentum). The intense focus on Christmas as one of Christianity's most important celebrations would come much later.
The moral of the story here is that we need to learn to be okay with the ambiguity of history. Baring some major archeological discovery (which is rare, but not out of the question), we will likely never know why we celebrate Christmas on December 25th—and we’ll likely never know the true date of Jesus’s birth.
What important, however, isn’t Jesus’s birthday. What’s important is what his life and ministry means for us today, and how we live out the truth presented by Jesus not just on December 25th, but every single day of the year.
Merry Christmas!
The early Church was actually hostile to celebrating birthdays. Origen of Alexandria (c.185-254 CE) declared them sinful, noting that in Scripture only sinful characters like Pharaoh and Herod celebrated birthdays (Homilies on Leviticus, Homily VIII). Early Christians focused instead on commemorating death dates, especially of martyrs, which they saw as births into eternal life. This makes Christianity's eventual embrace of Christmas as a celebration of Jesus's birth particularly fascinating.
This gets at a fundamental debate that would consume Christianity for centuries: when and how was Jesus divine? The Basilidians weren't alone in believing Jesus became divine at his baptism (called "adoptionism"). Others argued he became divine at his birth, while still others claimed he was eternally divine. These questions weren't definitively settled until powerful church leaders established the doctrine of the Trinity at the Council of Nicaea in 325 CE – and even then debates continued. Jesus himself never said he was God, nor taught anything about being part of a Trinity or being "one substance" with God the Father. These are inventions of his later followers.
P.F. Bradshaw, “The Dating of Christmas: The Early Church”, in T. Larsen (Ed.), The Oxford Handbook of Christmas (Oxford: Oxford University Press, 2020) 3-14.
According to Bradshaw, twenty-eight of Ephrem’s hymns focus on the celebration of Jesus’s birth on January 6. For more, see Kathleen E. McVey, Ephrem the Syrian: Hymns (New York: Paulist Press, 1989).
In 362 CE, Emperor Julian (called "the Apostate" because he rejected Christianity and tried to restore paganism) appears to have been the first person to suggest Christians chose December 25th to compete with a Roman sun festival. This is particularly ironic because Julian was actively trying to discredit Christianity and restore pagan worship at the time. Bradshaw, “Dating,” 7. You can also read Steven Hijmans’ 2003 article discrediting the idea Christmas was originally a pagan holiday.
Bradshaw, “Dating”, 9.
Because you follow the Roman Catholic Calendar introduced in 1582 by Pope Gregory XIII as a replacement for the Julian calendar, unlike the Orthodox Church which still celebrates the Nativity of Christ according to the Julian Calendar which was in place when He was born.