Why Is Christmas on December 25?

Every December, millions of people celebrate Christmas on December 25 — yet the Bible never gives a date for the birth of Jesus. So how did this particular day become Christmas Day? The answer is a mix of early Christian tradition, old calendars, and a choice that simply stuck. Here is the story, kept simple.

What the Gospels Do — and Do Not — Say

The Gospels of Matthew and Luke tell the story of Jesus’ birth — the journey to Bethlehem, the manger, the shepherds and the wise men — but neither names a day, a month, or even a season with certainty. Some readers point to details, such as shepherds watching their flocks at night, and argue about what time of year that suggests, but those clues have never settled the question. For the earliest Christians, the date mattered far less than the event itself.

In fact, for the first two centuries of Christianity, the birth of Jesus was not widely celebrated as a yearly feast at all. Easter, marking the resurrection, was the great festival of the early church. It was only later that Christians began to ask when the birth itself should be marked.

How December 25 Became the Date

By the fourth century, Christians in Rome were celebrating the birth of Jesus on December 25. We know this because a Roman calendar compiled in the year 354 lists December 25 as the birthday of Christ. From Rome, the date spread across the Western church, and over the following centuries it became the standard day for Christmas in the West.

That still leaves the question of why Rome chose that day — and here historians discuss two main ideas, neither of which can be proved with complete certainty.

Two Ideas Historians Discuss

The first idea is a piece of Christian arithmetic. Some early Christians believed that great events happened on the same calendar date, and they placed the Annunciation — when, in the Gospel of Luke, the angel tells Mary she will bear a son — on March 25. Count nine months forward from March 25, the length of a pregnancy, and you arrive at December 25. On this view, the date grew out of the church’s own calendar of sacred events.

The second idea looks at the Roman world around the church. Late December was already a festive time in Rome: Saturnalia, a popular midwinter festival of feasting and gift-giving, fell in mid-to-late December, and December 25 was associated with Sol Invictus, the “Unconquered Sun,” whose feast marked the turning of the year as the days began to lengthen. Some historians think the closeness of these festivals helped December 25 feel like a natural day for a Christian feast; others argue the Christian date was chosen independently and the overlap is coincidence. Scholars still debate how much influence, if any, the Roman festivals had — so it is best to treat this as a plausible influence, not a proven fact.

Why Some Christians Celebrate on January 7 — or January 6

December 25 stuck as the Western date, and most of the world now celebrates on that day. But many Orthodox churches still follow the older Julian calendar for their feasts. On that calendar, the December 25 celebration falls on January 7 in the modern Gregorian calendar — which is why Christmas in countries such as Russia, Ukraine, Serbia and Egypt is marked on January 7.

A few traditions keep yet another date: the Armenian Apostolic Church, for example, celebrates the birth of Jesus on January 6, together with his baptism. So while December 25 is the most widely used date, it is not the only one — and each date reflects the same celebration, kept on a different calendar.