By Erik Sietsema

If you Google “Why do we celebrate Christmas on December 25th,” you’ll get a slew of answers associated with a handful of popular theories. It is easy to just pick one and go with it, but this approach felt kind of uncomfortable to me. Many hours later, I have a rough answer, which is way too long. I also have an excess of background knowledge on all of the popular theories. If I address them all here, the article would be excessively long and most people will give up long before they find out the answer.

I will dig into the background information and various theories on patchingcracks.com. This article is just going to look at the why we celebrate Christmas on December 25th. Perhaps the most basic fact to establish in answering the question is to look at when the observation first began.

When did December 25th begin as the observation of Jesus’ birthdate?

The earliest record of Christians observing the birth of Jesus on December 25th is an ancient document called the Depositio Martirum. It is the oldest surviving liturgical calendar and was assembled in 336 AD, around 10 years after Emperor Constantine made Christianity legal through the Edict of Milan. It’s important to understand that Constantine did not make Christianity the official religion of Rome. He just made it legal. Up until that point, there were some localized instances of amnesty being given to Christians by various officials in an effort to encourage them to join the army. Those found guilty of being Christians were punished and had all of their property confiscated.

The end to the outlaw status of Christianity made it possible for Christian leaders to gather, collaborate, and discuss beliefs/practices with bishops from other parts of the empire. The first meeting was known as the Council of Nicaea. There is no record of them discussing the date at that time. However, there is some supporting/compelling evidence that the date was not established at this time or in 336 when the calendar was assembled, but rather predates Nicaea and the Depositio Martirum, reaching back at least into the late second century. We’ll look at some of it here.

Didn’t Christians just take December 25th as the birthdate of Jesus because pagans were already celebrating that day?

This is a popular theory that didn’t actually show up until the 1800s. There are no ancient documents that say or infer that this took place. There is a great deal to look at regarding this idea. So much so that it is impossible to really dig into it here without getting bogged down. So, I will briefly state a few things and move on. Christians may have done this specifically to avoid persecution for their feast days, as it wasn’t unheard of for them to be persecuted for not celebrating pagan holidays. There is no evidence of this practice. In fact, quite the opposite is true. Christians were very careful to avoid anything close to paganism so that it wouldn’t be integrated into the church. There are tons of examples from before the edict of Milan where the church strove to avoid exactly that. Further, there is a case to be made that Natalis Sol Invictus was placed on the 25th specifically because the church was celebrating Jesus’ birth on that date.

Isn’t December 25th just 9 months from March 25th, the day of the annunciation?

This is the other theory that turns up prominently in history. It actually has quite a bit of support. The argument goes like this: The church observes the date of the angel announcing the immaculate conception to Mary on March 25th. 9 months after conception, he was born… on December 25th. This makes sense and fits the liturgical calendar.

In the late 4th century, Augustine mentions that the church observed March 25th as the annunciation. This is a widely accepted explanation for the birthdate and is plausible. Augustine is not a minor voice amongst the ancients. The 9-months-from-the-annunciation approach is going to come up a few times in this discussion, because it’s prominent in ancient history.

However, there are issues with the approach. For starters, the natural follow up question is how the date of the annunciation was determined. Augustine asserts that March 25th is the date of the annunciation based on an ancient theory that prominent people died on the date of their conception. He cites March 25th as the date of the crucifixion, due to the conception/death thing. When he mentions December 25th, he describes it as based on “tradition” and doesn’t mention the 9-month gap.

Most modern folks will balk at the death/conception thing. However, there is another problem. Based on the data we encounter in the gospels, Jesus was crucified and buried on the Friday of Passover on the 14th of Nissan (Jewish calendar). There were only two instances of Passover Friday landing on the 14th of Nissan during Pilate’s time in office. One was in 30 AD, which is too early to be correct. The other was April 3, 33 AD, which is almost certainly the correct date. This suggests that Augustine didn’t pick the annunciation date from the date of the crucifixion, primarily because he got it wrong and likely had no idea when it actually took place. Logically, we can infer that he got his information using either the birth or conception date as a starting point. I would argue that it’s likely that Augustine’s March 25th/December 25th dates came either directly or indirectly from an earlier source.

In the surviving works from the early church, there is an instance of identifying March 25th as the conception date. In the late 2nd/early 3rd century, Sextus Julius Africanus set the day of the incarnation on March 25th. From this, the December birth date is simply a 9-month difference. This would mean that Augustine’s incorrect date for the crucifixion was a result of his using the death/conception theory to set the date of the crucifixion based on the date of conception. His wording points to the idea that he had December 25th and worked out March 25th based on the 9-months between conception and delivery.

Who was Sextus Julius Africanus and where did he get March 25th?

Sextus Julius Africanus was born in160 AD in Jerusalem. He was well-educated and traveled extensively in his youth. Later, he served as ambassador to the city of Rome, where his extensive learning so impressed Emperor Alexander Severus that he appointed Africanus to build the library at Pantheon. During his life, Africanus wrote extensively, including a 5 volume history of the world, which is now lost. Fragments of that work have survived and his reputation as a brilliant scholar was voiced repeatedly by other authors whose works survive today.

Africanus’ 5 volume work, The Chronography, attempts to establish a timeline for world history from what he thought was the date of creation. He places the birth of Jesus on March 25th, though working this out from his writings is difficult because there are three calendar systems involved.

Based on the few surviving lines on the topic, it seems as

though he places the annunciation on the first day of the 5501st year after the first day of creation. As I understand it, if we line that day up with the Jewish calendar and translate it to the Julian Calendar, we get March 25th. This may be the earliest surviving reference to the annunciation landing on that day. Again, from that day we get December 25th as the birth date 9-months later.

Unfortunately, we lack the majority of Africanus’ work, so it’s hard to know the details of his argument. I think it is possible that he used a date he received through tradition and factored it into his calculation of the date of creation. This would mean he used a date (December or March 25th) as a starting point. Either way, it seems as though this is the earliest mention of the March 25th date, which then places December 25th as the birthdate.

Could the March and December dates be older than Africanus’ work?

It is possible that Africanus got his dates from tradition handed down to him. Augustine refers to the December 25th as a tradition along with a couple of other early church fathers. There are some records of the early church fathers debating the birthdate, though none of them seem to put a great deal of importance on the matter.

There is also an interesting tidbit from the Council of Nicaea. As I said earlier, this was the first time since the first century that the leaders of the early church could gather. They used the opportunity to take care of a large number of issues. Among others was adjusting the calendar. Because days in the Julian calendar were about 11 minutes off, it gained days periodically. By the time the council gathered in the early fourth century, the winter solstice had drifted off of December 25th. At that time, it was on December 23rd. The council agreed to change it. Why does this matter? If the council was already looking at December 25th as the birthdate of Jesus, then it would be associated with the winter solstice. Their concern over where the solar calendar landed in relation to the Julian Calendar makes sense if they associated the solstice with the birth of Jesus.

That would mean that the birth date and the solstice were potentially connected much earlier, perhaps as early as when the two actually landed on the same day a couple of centuries beforehand.

Wasn’t Jesus probably born in the spring?

Before digging into the Biblical accounts, it is necessary to look at this topic.

In commentaries and theological literature it is popular to assert that Jesus was born in the spring because shepherds would not have kept their flocks in the fields during the winter due to the cold weather. In fact, I found references (that I haven’t double checked yet) pointing out that ancient rabbis instructed shepherds to come in from the fields with their flocks at a certain point in the calendar year due to weather.

This means that a December date could not have been witnessed by the shepherds in Luke’s gospel. The information about the weather is partly correct, but the theory itself is incorrect. In fact, most shepherds went in for the winter. The Talmud specifically says that sheep raised specifically for temple services were to remain in the field year-round. The fields where the temple flocks were kept would have been in the area of Bethlehem. So, the shepherds who raised the lambs that were sacrificed in the temple would have been in the field in December and would have been perfect witnesses for the birth of the man who would be called the “Lamb of God.” (Note: the Talmud is a collection of teachings from rabbis beginning several hundred years before Christ was born and running until a few hundred years after.)

The point of this excerpt is to say that eliminating the December date based on the winter weather driving shepherds in for the season is not a legitimate argument. And to suggest that the December date would allow for a cool connection, of the sort we often see in the life of Jesus.

Is there anything in the Bible to support December 25th as the Birthdate?

This is a great question because the primary eye witnesses to the life of Jesus are contained in the Bible. As to whether there is support for December, I have a vague answer: Sort of.

If we look at the events of the gospels and line them up with events we can solidly date, we can approximate the birth date of Jesus. Part of what makes this tricky is that Matthew and Luke, who both relate the story of Jesus’ birth with more detail, emphasize different aspects of the events. This is further complicated by the fact that they don’t offer much in the way of time indicators.

The result is a couple of potential timelines based on the material we have available. This is very much in keeping with the ancient Jewish style of recording history and events. For those of us who are concerned more with timelines and pinning down dates, it can be a bit frustrating.

When talking about the birth of Jesus, one of the principle figures is King Herod the Great. The gospels record his death after the killing of the newborns in Bethlehem. We can identify the date of his passing based on the work of Josephus, an ancient Jewish historian.

Josephus records an event that happened near the time of his passing in which an eclipse took place during the execution of several Jewish men who had reacted to rumors of the tyrant’s death by removing a Roman eagle that Herod had placed over the temple gates.

A total eclipse took place on January 10th, 1 BC; which most scholars agree was the date of the executions. Based on that solid date, it is possible to line up the events of Herod’s final months as recorded in the gospels and Josephus’ work and estimate the date of Herod’s death.

Applying the events in the gospel narrative to that time table offers a range of potential birthdates for Jesus. The final outcome allows for December 25th as a very plausible date for the nativity.

Another detail included in Luke’s gospel relates to Mary visiting Elizabeth during the fifth month of her pregnancy. The visit seems to be in response to the angel’s visiting Mary and likely took place not long after the annunciation.

The gospel of Luke also includes the account of Zechariah encountering an angel who announces Elizabeth’s pregnancy. At the time, he was serving in the temple. Luke includes the specific priestly division that Zechariah belonged to: Abijah.

The Talmud tells us that the Abijah division was serving in the temple when it was destroyed in 70 AD. Scholars have attempted to reconstruct the dates and ordering of the various divisions’ service based on details in the Talmud regarding the temple’s destruction, services, and information gleaned from Josephus’ works.

Service duty ran in 24-year cycles allowing each division of priests one opportunity to serve every 24 years. This means we can count backward in 24 year increments to determine when the Abijah division served and potentially date the announcement to Zechariah.

Based on this approach, Zechariah would have been serving in 3 BC. That gives us a couple potential dates for the conception of John the Baptist. One of those dates results in John being born on the Autumnal Equinox. Incidentally, ancient tradition holds that the Autumnal Equinox was the date of John’s birth.

Around 6 months later, Jesus would have been born on the winter solstice, or December 25th.

It’s important to note that these dates are estimates based on existing data. For brevity I have excluded a lot of detail… and it was still way too long. I will do my best to cover all the details in follow up posts on my blog in the coming days.

1. December 25th as the birth of Jesus first appears on a liturgical calendar in 336, but there’s evidence it was celebrated earlier than that.

2. The earliest written work we have that supports December 25th is a fragment from Sextus Julius Africanus’ work from early in the late 2nd or early 3rd century. He attempted to calculate the date. Though, his work could have used the traditional dates for the annunciation and Christmas to calculate the rest of history.

3. Using the Bible, the Talmud, and the work of Josephus we can make a case for December 25th.

If you disagree or have questions, reach out to me or check out my blog. Patchingcracks.com, 406-399-3803, pastorerik@bigsandychurch.org.