Why we celebrate Christmas on December 25

No one knows exactly when Jesus was born because the Bible doesn’t give us a specific date.

And the Bible doesn’t tell us, in large part, because the first generations of Christians just didn’t really care. Celebrating births was seen as more of a pagan tradition and something that, for the first few centuries, the church tried to distance itself from.

The Epiphany, the date that commemorates the coming of the wise men, was actually a much more significant day for much of Christian history, even after people started celebrating Christmas.

For example, the old English carol “The Twelve Days of Christmas” actually begins on December 25 and culminates on January 6, with the largest celebrations historically reserved for the latter date.

But if the Bible doesn’t tell us when Jesus was born and it took Christians a few centuries to start celebrating his birth, how did Christmas end up on December 25?

Was Jesus born in the fall?

There are good reasons to believe that Jesus was actually born sometime in late September to early October.

For example, it is thought that Zacharias—the Father of John the Baptist—likely entered the temple to burn incense in mid-June, which would have put John’s conception later that month.

Given that Elizabeth was six months pregnant when the angel came to see Mary (Luke 1:26), that would put Christ’s birth in the fall of the next year. However, because Scripture doesn’t tell us when Zacharias encountered the angel and we are left to rely on tradition for that dating, there is room for disagreement.

The earliest dating of December 25 goes back to the 200s, when a tradition began to circulate that Jesus was conceived on the same day that he was crucified.

Since Tertullian dated the crucifixion to March 25, nine months after that would have meant that Jesus was born on December 25. The idea that Jesus was conceived on the same day that he died is also not found in Scripture, but it became popular enough that most accepted it without giving it too much thought. By the time of Augustine, that belief had become common knowledge, and he incorporated it into his treatise On the Trinity.

However, our celebration of Christmas on December 25 is not due solely—or even primarily—to this theological quirk.

Sharing a birthday with the gods

In addition to the dating from Christian sources, December 25 has been an important day for cultures throughout much of human history.

The winter solstice was often celebrated around that time—which is the origin, in some ways, of our Christmas trees—and, by the first century, two significant Roman feasts occurred on December 25.

The first was the Feast of Saturnalia. Saturn was the Roman sun god, and, since the solstice commemorated the days beginning to get longer, people feasted and shared gifts in his honor.

The second major feast was the birthday of Mithra.

By the third century, Mithraism was quickly becoming one of the most popular mystery cults in the Roman world and was especially significant in the army. Mithra was their sun god, and they actually had several traditions in common with Christians.

For example, they practiced baptism—though by the blood of a bull instead of water—as a way of initiating new members. They believed in the “unconquered one” who served as a mediator between the light and the darkness, while also functioning as a revealer of truth. And they had a fairly well-developed theology of the afterlife, which was not overly common back then.

Both of these celebrations are important for the dating of Christmas because when Constantine—the Roman emperor who legalized Christianity—ascended to the throne and began encouraging people to convert, making a bigger deal out of Christmas was part of his approach. Because Romans already had significant festivals in place worshiping the birth or rebirth of some of their gods on December 25, it was easier to ask them to keep the parties but make them about Jesus than give up a popular celebration altogether.

So, in 336, Constantine formally declared that the celebration of Christ’s birth would occur on December 25. For the most part, it’s stayed that way ever since.

Accommodating the culture for Christ

Does knowing a bit more about the pagan and theologically questionable background to our celebration of Christmas on December 25 change the way you see the holiday?

For some, it might.

The Puritans, for example, essentially banned any large celebrations of Christmas because of those connections, and their hesitance persisted until the mid-to-late 1800s for most Americans.

But Christians have been taking pagan or cultural beliefs and recontextualizing them in ways that point people back to Jesus for much of our history, often to great effect.

Rather than dwelling on the degree to which Constantine’s motivations for setting the date diminish Christmas, let’s focus instead on whether aspects of our culture could be used for a similar purpose.

With Halloween, for example, giving out tracts with candy—and note I said with candy rather than in place of candy—or hosting trunk-or-treats the weekend before at our churches can be a great way to take a fun celebration that has little to do with Jesus and use it as a way to share the gospel.

It’s certainly possible to go too far with such efforts and cross into heresy—which is why allowing God to guide our plans is so important—but we could do far more for the kingdom if we looked for ways to accommodate the culture rather than asking the culture to accommodate us.