Why is Christmas on December 25?
Source: Haaretz latest headlines
If you open the New Testament looking for the date of Jesus’ birth, you will not find it. The Gospel of Luke recounts a census under Caesar Augustus and shepherds watching their flocks by night. Matthew describes a star, Magi from the East, and a flight to Egypt. Neither mentions a month, a day, or even a season. Mark and John skip the birth entirely.
For the first two centuries of Christianity, this silence does not seem to have troubled anyone. Early Christian writers did not celebrate birthdays and often viewed them with suspicion. Writing around 245 C.E., Origen of Alexandria remarked that in Scripture only sinners – Pharaoh and Herod – celebrate their birthdays. For early Christians, the central date was not birth but death: Easter, the crucifixion and resurrection.
Yet within a few centuries, Christians across much of the Roman world were celebrating the birth of Jesus on December 25. When and why did this change?
The date appears
The first solid evidence of Christmas arrives abruptly in the 4th century. It appears not in a sermon or a gospel commentary, but in a calendar.
The Chronography of 354, an illustrated almanac prepared for a wealthy Roman Christian named Valentinus, contains a list of martyrs’ feast days used by the Roman church. At the top of the list, eight days before the Kalends of January, is a brief entry: natus Christus in Betleem Judeae. Christ was born in Bethlehem of Judea. The date is December 25.
The list itself is generally thought to reflect Roman practice as early as 336 C.E. By that point, the church in Rome had settled on a birthday for Jesus. But Rome was not the Christian world.
Two birthdays, one problem
Elsewhere, things looked different. In much of the Greek-speaking East – Alexandria, Antioch, and Jerusalem – Jesus’ birth was celebrated on January 6, a feast later known as Epiphany. This date marked not only the Nativity, but also Jesus’ baptism. The birth was folded into a broader revelation of Christ to the world.
The coexistence of two birthdates created pressure. By the late 4th century, church leaders began pushing for unification. In Antioch, the transition can be observed almost in real time. In a sermon delivered in 386 C.E., John Chrysostom urged his congregation to adopt December 25, stressing that the feast was a recent import from the West and noting that it had been unknown in the city only a decade earlier. His sermon captures a moment of transition, when the Roman date was still new, contested, and in need of explanation.
The exhortation worked. By the early 5th century, December 25 had spread across most of the Christian world. Jerusalem held out longer. The Armenian church never switched at all, preserving January 6 to this day.
Which only sharpens the question: why had anyone decided Jesus was born on either date in the first place?
The Pagan explanation
The most familiar answer is that Christmas was deliberately placed on the same day as a pagan festival: the Dies natalis solis invicti, the “Birth of the Unconquered Sun.” According to this theory, the church co-opted a popular solstice celebration and rebranded it.
This idea emerged in the early modern period, when Protestant scholars began questioning the legitimacy of church traditions that lacked clear biblical grounding. In the late 17th and 18th centuries – especially in Calvinist circles – writers argued that December 25 was a pagan import, absorbed by the church as Christianity spread through the Roman world.
In the 19th century, this polemical claim was upgraded to a scholarly theory. Figures such as the German philologist Hermann Usener systematized it within the emerging “history of religions” approach, turning what began as a Protestant critique of Catholic practice into what would become the standard modern explanation.
It is neat, cynical – and increasingly difficult to sustain.
The 4th-century emperor Aurelian did promote a cult of Sol Invictus in 274 C.E., but there is little evidence that December 25 functioned as a major pagan festival before his time . Earlier Roman calendars list solar observances – just not on this date.
In fact, the same document that provides our earliest clear evidence for Christmas itself also supplies the main evidence for a pagan festival on December 25. The Chronography of 354, which, as we have seen, preserves a Roman list of feast days reflecting practice as early as 336 C.E., records both the birth of Christ and the Birth of the Unconquered Sun on that day.
Even here, however, the pagan entry looks odd. It notes a celebration of the “Birth of the Unconquered One” accompanied by 30 chariot races. Roman games were normally held in multiples of twelve, allowing fair rotation among the racing factions. Thirty does not fit the pattern.
As the historian Steven Hijmans has argued, this irregularity makes the pagan festival look less like an ancient, established tradition and more like a late or improvised addition to the calendar – possibly reacting to an already existing Christian feast rather than preceding it.
This does not mean the date was symbolically meaningless. Late-antique Christians were fully aware of the solstice’s cosmic significance.But aligning Christ with the return of light was not the same as adopting a pagan cult or festival. When John Chrysostom preached Christmas in Antioch in 386 C.E., he did not invoke sun gods or Roman rites. He spoke instead of Bethlehem replacing the heavens themselves, and of Christ as the “Sun of righteousness,” born as the natural light of the world begins to increase.
In other words, the pagan feast may not be the source of Christmas. It may be its echo.
Calculation, not celebration
An alternative explanation begins not with Roman festivals but with late-antique chronography.
Early Christians were intensely concerned with dating the crucifixion, which they regarded as the central event of salvation history. By the 2nd and 3rd centuries, many Latin Christians – especially in Rome and North Africa – had settled on March 25 as the historical date of Jesus’ death, based on their own reconstructions of the Passion.
From there, a theological assumption came into play – one with clear parallels in Jewish thought. Rabbinic sources such as the 2nd-century Seder Olam Rabbah, a chronological work dating biblical events, and later the Talmud, preserve the idea that great figures live “integral” lives: they die on the same calendar date on which they were born or conceived. Moses, according to Kiddushin 38a, was born and died on the 7th of Adar.
Applied to Jesus, the logic was straightforward. If his death was believed to have occurred on Passover – and if that Passover was fixed, through chronological reconstruction, to March 25 – then his conception was assumed to have taken place on the same date. Adding a symbolic nine-month gestation led to December 25.
It is not entirely clear how this shift from birth and death on the same date, to birth and conception on the same date should be understood. On the one hand, early Christians did assign real theological weight to conception as the moment the divine entered history, and the Annunciation story appears prominently in the Gospels themselves. Treating conception as a decisive sacred event was therefore not artificial.
On the other hand, the move was also mathematically convenient. Identifying March 25 as the date of conception, rather than birth, allowed the chronology to resolve neatly with a Nativity on December 25. Both impulses may have been at work at once: genuine theological interest in conception, and a desire for a coherent, symmetrical calendar.
This line of reasoning appears in Christian sources well before Christmas enters the liturgical calendar. Sextus Julius Africanus, an early Christian traveler writing around 221 C.E., links the conception of Jesus to March 25 as part of a broader chronological scheme.
A chronicle attributed to Hippolytus of Rome goes further: it places the creation of the world on that same date and calculates Jesus’ birth as occurring 5,502 years and nine months later – again, December 25. These are not festive texts. They are exercises in sacred arithmetic.
A second calculation – and a mistake
There was also another, more concrete attempt to anchor the Christian year to Jewish sacred time. Early Christian writers reading Luke 1 assumed – incorrectly – that Zechariah, the father of John the Baptist, was serving as high priest in the Temple on Yom Kippur when he encountered the angel. From that assumption, they built a timeline.
If Zechariah’s vision occurred in late September, John would have been conceived then and born nine months later, around June 24. Luke states that Jesus was conceived six months after John, placing the Annunciation around March 25 – and the birth nine months after that, on December 25.
The premise was wrong, but the effort is revealing. These writers were not looking to Roman cults. They were trying, however clumsily, to synchronize the story of Jesus with the Jewish liturgical calendar.
Why January 6 in the East?
The same logic helps explain why Eastern churches arrived at a different date. In parts of the Greek-speaking world, Jesus’ death was calculated not as March 25 but as April 6. Applying the same symmetry – linking death and conception – produced a conception date of April 6 and, nine months later, a birth date of January 6.
But the sequence may also have run in the opposite direction.
January 6 may first have emerged as a ritual date in 4th-century Palestine not through calculation, but through practice. As pilgrimage to the Holy Land expanded, Christians sought fixed days on which to commemorate events tied to specific locations in Jesus’ life. Bethlehem and the Jordan River were obvious focal points, and a single feast marking both Jesus’ birth and his baptism would have suited the rhythms of pilgrimage and local devotion.
Why January 6, in particular, became associated with these commemorations is unknown. The sources offer no explanation, and the choice may reflect a local custom or circumstance that has since been lost. Chronological arguments may then have been developed to justify an already established date. Later, in the West, these calculations were adjusted to place Jesus’ birth not on January 6 but on December 25 – a date with far greater symbolic weight as the winter solstice.
An unfinished case
None of this yields a single, definitive answer. December 25 was not simply borrowed from a pagan festival – but neither does it preserve a living memory of Jesus’ birth. It emerged from a convergence: Jewish chronographic assumptions, Christian efforts to date the Passion, symbolic meanings attached to the solstice, local liturgical practices, and the slow, uneven standardization of the church calendar.
What can be said with confidence is this: Christmas was not fixed because anyone knew when Jesus was born. It was fixed because late-antique Christians were convinced that sacred history possessed an underlying order – one that could be aligned, justified, and sometimes retrofitted through calculation, symbolism, and practice alike.
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