Why Is Christmas on December 25? | The Shape of the World

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Updated: November 14, 2026

Every December, about two billion people around the world mark Christmas on the twenty-fifth. Here is the strange part. The Bible never gives a date for the birth of Jesus. Not a day, not a month, not even a season. The Gospels tell the story of the birth in detail, and they leave the calendar blank. So where did December twenty-fifth come from?

Rome, 336 AD

The first solid record we have comes from Rome. A Roman almanac called the Chronograph of three hundred fifty-four lists the feasts of the church, and under the year three hundred thirty-six it records, in Latin, that Christ was born in Bethlehem of Judea on December twenty-fifth. That is the earliest surviving written evidence of Christmas on this date.

The first clue sits in the sky. On the Julian calendar, the calendar Rome used, the winter solstice fell on December twenty-fifth. That is the shortest day of the year, the turning point when the days start getting longer again. In our modern Gregorian calendar the solstice falls around December twenty-first.

Rome in December was already a party. The biggest festival was Saturnalia, a week of feasting, gift giving, gambling, and role reversal in honour of Saturn, the god of agriculture. There is one problem with that story. Saturnalia ran from December seventeenth to December twenty-third. It ended two full days before December twenty-fifth.

A second Roman festival fits the date exactly. In the year two hundred seventy-four, the emperor Aurelian built a great temple in Rome to Sol Invictus, the Unconquered Sun, and set its birthday on December twenty-fifth. The earliest secure record of a sun festival on December twenty-fifth is the same Roman almanac from three hundred fifty-four that records Christmas, and no ancient Christian writer says the date was chosen to copy it.

There is a second explanation, and it comes from inside the church, from arithmetic. Early Christians believed that great lives began and ended on the same calendar day. Following the writer Tertullian around the year two hundred, they believed Jesus died on March twenty-fifth. Nine months after March twenty-fifth is December twenty-fifth. The date may have been calculated, not copied.

So here is where the story stands, honestly. Documented fact: the first clear record of Christmas on December twenty-fifth is Rome, three hundred thirty-six. Documented fact: the emperor Aurelian honoured the Unconquered Sun in two hundred seventy-four, and the Julian solstice fell on December twenty-fifth. Documented fact: early Christians did the March twenty-fifth plus nine months calculation. Unproven: the claim that the church deliberately copied the sun festival to win over pagans. That idea first appears in a twelfth century manuscript note, eight hundred years after the event.

How the date travelled

Once Rome chose December twenty-fifth, the date travelled, and it travelled slowly. The churches of the East had their own date, January sixth, when they marked the birth together with the visit of the wise men and the baptism of Jesus, a feast we now call Epiphany. The East eventually accepted December twenty-fifth for the birth and kept January sixth for the visit of the wise men. Christmas did not gain its own full liturgy until the ninth century, five hundred years after that first Roman record.

The traditions that came later

The Christmas we recognise, the trees and the stockings and the big family dinner, came much later still, and almost none of it is Roman. The Christmas tree comes from Germany, where devout Christians in the sixteenth century began bringing decorated fir trees into their homes. It stayed a German custom for three hundred years, until an engraving in the Illustrated London News in eighteen forty-eight showed Queen Victoria and Prince Albert gathered around a tree at Windsor Castle. A German habit went global because a royal family was pictured with it.

Santa Claus is a similar patchwork, stitched together over centuries. He starts with Saint Nicholas, a fourth century bishop of Myra, in what is now Turkey, famous for secret gift giving. Legend says he dropped bags of gold through a window to save three sisters from poverty, and that story is the ancestor of the stocking by the fireplace. The sleigh and the eight reindeer arrived in eighteen twenty-three, in A Visit from Saint Nicholas.

What we actually know

That is why the shepherds matter, and why they are the best clue in the whole story. Luke's Gospel says shepherds were living out in the fields, keeping watch over their flocks by night. Around Bethlehem, December is cold and rainy, and flocks were usually brought in by October. That points to a birth in the warmer months, and it is one reason most scholars think December twenty-fifth is a chosen date, not a remembered one. So what do we actually know? The Gospels give no date. Rome was celebrating Christmas on December twenty-fifth by three hundred thirty-six. The Julian solstice fell on that day, and early Christians calculated March twenty-fifth plus nine months and got December twenty-fifth. What we do not know is which of those reasons tipped the balance. The sun was turning, the calendar was ready, and the arithmetic worked.

Sources and further reading

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