A question I am asked every year at Christmas time is this: How do we know that Jesus was born on December 25th? The most honest and credible answer I can give to this question is that we don't know if this was the date when Jesus was born. When I share this answer with people, the responses range from being scandalized to "oh, okay." For some, their strong reactions would lead some to think that the entirety of the Gospel message hinges on Jesus being born on December 25th. The fact of the matter is that nothing of Christian faith would be compromised if Jesus were born on a different date. In fact, there is a good chance that Jesus wasn't born on December 25th for reasons that have nothing to do with the feast days of pagan gods. Let's take a look at what I mean.
Problem One: Were Birthdays Celebrated at the Time of Jesus?
To begin with, the first stumbling block we need to overcome with trying to know when Jesus was born is the fact that the Bible doesn't give us a date for his birth. In fact, only two of the four Gospels even deal with the infancy of Jesus. Therefore, our first question to ask is this: If the actual date of Jesus' birth was so important, then why didn't all four Gospels not only have an infancy narrative, but strongly emphasize the date when Jesus was born? Of the many answers that could be given, I find the simplest answer to be that we need to first see the birth of Jesus through Jewish eyes.
In Jewish culture, one did not celebrate the birth of a child. In fact, the Jewish people at the time of Jesus distained the celebration of one's birth because that's what the pagans of the Roman Empire celebrated. Therefore, we need to realize that the culture from which Christianity emerged did not emphasize the celebration of birth.
So, if Jewish custom preferred not to celebrate one's birth, what was the day of significance that was celebrated? In Jewish culture, it was an ancient custom that is now called the yahrzeit, or the day of one's death. The modern celebration of the yahrzeit differs slightly from the practices at the time of Jesus, but the essence of the remembrance was that the family would commemorate the death of a loved one each year on the day they died. Families would fast and light a candle for twenty-four hours to commemorate the day.
I find it a tantalizing parallel the what was seen as of utmost importance to the early Christians was the celebration of the day Jesus rose from the dead. This commemoration was not remembered with fasting, but feasting with what we would call today the Mass. So central was this mystery that it was celebrated every week, not as a "go to Mass or else" mentality, but to celebrate every Sabbath as the Day of Resurrection. Therefore, whether it be the candles we light at Mass, the vigil lamp by the tabernacle where the Eucharist is reserved, or a devout mother lighting a votive candle on the anniversary of her son's death, I can't help but see a hint of the ancient practices of Judaism that led to the yahrzeit. This intuition is strengthened by the fact that the celebration of Christmas was a later development and not part of the earliest feasts of the Church. In regard to the Lord's Day, the weekly celebration of the Lord's Resurrection was foundational.
Problem Two: Different Ways of Measuring Time.
So, can we find December 25th referenced as the date of Jesus' birth in the writings of the early Church Fathers? Yes, we can... with some presumptions that are VERY important to take into account. A basic Google search on when we find the first reference to December 25th as the date of Jesus' birth will bring you to Hyppolytus of Rome (170AD - 235AD). Most online citations will boldly affirm that Hyppolytus wrote that Jesus was born on December 25th. The problem is, that's not what Hyppolytus said. He actually said that Jesus was born on the 25th day of the ninth month. What Hyppolytus is referencing is the Jewish month of Kislev. Of particular interest, the 25th of Kislev in Jewish culture is the celebration of Hanukkah or the "Feast of Lights." Might there be a connection being made between this Jewish feast and Jesus as the "light of the world?"
To get from the 25th of Kislev to December 25th, we first make a pit stop at the Julian Calendar, which was determined to be slipping each year through the work of the first Vatican Observatory in the Tower of the Winds, leading to the reformed Gregorian Calendar. The Christian West embraced the Gregorian reforms while the Christian East chose to remain on the Julian Calendar. This is why, to this day, there are two dates in the Christian world for the celebration of Jesus' birth: December 25th in the Christian West and January 7th in the Christian East. Further, we see that the Jewish calendar is a lunar calendar so the 25th of Kislev, Hanukkah, seldom coincides with December 25th. In short, the presumption of when Jesus was born is far more difficult to pin down than one would think.
This, of course, all presumes that the 25th of Kislev was the date of Jesus' birth. The first reference to any date of Jesus' birth comes from Clement of Alexandria (150AD-215AD). When reworking the ancient calendars to coincide with the Gregorian calendar, the date you arrive at is November 18th. Other traditions put that date at January 6, May 20th, and if you want to play with the idea of the Star of Bethlehem as a naturally occurring phenomenon like a planetary conjunction, you can find dates all over the place. In other words, if you have the right amount of obsessive compulsive tendencies, you can find a number of dates when Jesus might have been born.
Problem Three: What Does the Birth of Jesus Teach Us?
My priestly intuition often wonders if the misplaced obsession people have about the date of the birth of Jesus has more to do with internal fears versus anything to do with Christmas. Living in an American culture that is becoming increasingly aggressive against Christianity, I find Christians (myself included) feeling defensive as if we have to constantly prove our faith to the growing atheistic worldview. This fear based, defensive stance can lead to an interesting type of literalism in which things like the date of Christ's birth become an apologetic to prove that Jesus did exist. If this is the case, one can look in many places to affirm that Jesus of Nazareth walked this earth with no need of dealing with Jesus' birthday. Anyone who has studied ancient theologians or philosophers knows the biographic headaches in research as the date of birth is often given in ranges and not a clean date. In short, inability to pinpoint the date of someone's birth in the ancient world did nothing to question their existence or change what they taught.
What I find far more meaningful when exploring questions like the date of Christmas are the spiritual and metaphorical interpretations of why Jesus' birthday is celebrated when it is. I mentioned earlier how the connection between Jesus' birth and the date of Hanukkah provide a fascinating parallel between "The Feast of Lights" in Jewish tradition and the birth of him who is the "Light of the World" in the Christian tradition. To further this connection, Pope Emeritus Benedict XVI, writing as Joseph Cardinal Ratzinger, in his book The Spirit of the Liturgy explains how the birth of Jesus is celebrated at about the time of the Winter Solstice when the days are shortest and the nights are long. However, after Christmas, the days eventually begin to lengthen, pointing to the hope of Easter's spring and new life. The symbolic significance of this "Cosmic Liturgy" is that creation is showing us that, when Christ enters the world, the light overcomes the darkness. Of course, this interpretation only works in the Northern Hemisphere. Could it be that the globalization of Christianity should seek new symbol systems based on our modern understand of time and space to clearly express the inspired truth that God has come to meet his people in the Person of Jesus Christ?
At this point, I presume some of you may have officially labeled me the "Christmas Kill-Joy" with all this speculation about the birthday of Jesus. Perhaps, but the intent of this post was to help all of us, myself included, to keep from falling into the trap of misplacing our spiritual attention upon the superficial aspects of Christmas that mean very little when reflecting upon the core message of this season.
And what is this message: In the person of Jesus Christ, God has met his people who waited for the Lord's coming. In light of this truth, we rejoice on Christmas Day! Therefore, I wish to extend to all of you who read The Catholic Astronomer a very Merry Christmas and a most Blessed New Year!