Merry Christmas! But why do we celebrate it today?

Merry Christmas everyone! Here is something you probably didn't know about Christmas:

On December 25, Christians around the world will gather to celebrate Jesus’ birth. Joyful carols, special liturgies, brightly wrapped gifts, festive foods—these all characterize the feast today, at least in the northern hemisphere. But just how did the Christmas festival originate? How did December 25 come to be associated with Jesus’ birthday?

The Bible offers few clues: Celebrations of Jesus’ Nativity are not mentioned in the Gospels or Acts; the date is not given, not even the time of year. The biblical reference to shepherds tending their flocks at night when they hear the news of Jesus’ birth (Luke 2:8) might suggest the spring lambing season; in the cold month of December, on the other hand, sheep might well have been corralled. Yet most scholars would urge caution about extracting such a precise but incidental detail from a narrative whose focus is theological rather than calendrical.

The extrabiblical evidence from the first and second century is equally spare: There is no mention of birth celebrations in the writings of early Christian writers such as Irenaeus (c. 130–200) or Tertullian (c. 160–225). Origen of Alexandria (c. 165–264) goes so far as to mock Roman celebrations of birth anniversaries, dismissing them as “pagan” practices—a strong indication that Jesus’ birth was not marked with similar festivities at that place and time. As far as we can tell, Christmas was not celebrated at all at this point.

Finally, in about 200 C.E., a Christian teacher in Egypt makes reference to the date Jesus was born. According to Clement of Alexandria, several different days had been proposed by various Christian groups. Surprising as it may seem, Clement doesn’t mention December 25 at all. Clement writes: “There are those who have determined not only the year of our Lord’s birth, but also the day; and they say that it took place on (May 20 in our calendar), or (March 21), or (April 21), or (April 15), or (April 20 or 21).”

Clearly there was great uncertainty, but also a considerable amount of interest, in dating Jesus’ birth in the late second century. By the fourth century, however, we find references to two dates that were widely recognized—and now also celebrated—as Jesus’ birthday: December 25 in the western Roman Empire and January 6 in the East (especially in Egypt and Asia Minor). The modern Armenian church continues to celebrate Christmas on January 6; for most Christians, however, December 25 would prevail, while January 6 eventually came to be known as the Feast of the Epiphany, commemorating the arrival of the magi in Bethlehem. The period between became the holiday season later known as the 12 days of Christmas.

So, almost 300 years after Jesus was born, we finally find people observing his birth in midwinter. But how had they settled on the dates December 25 and January 6?

The first theory is popular (based on existing pagan celebrations) but doesn't hold up under further analysis- early Christians rejected pagan connections and tried to be different, and there isn't even a hint mentioned that Christmas was based on pagan traditions until the tenth century. So I reject this theory and instead point you towards the second (lesser known) one:

Around 200 C.E. Tertullian of Carthage reported the calculation that the 14th of Nisan (the day of the crucifixion according to the Gospel of John) in the year Jesus died was equivalent to March 25 in the Roman (solar) calendar. March 25 is, of course, nine months before December 25; it was later recognized as the Feast of the Annunciation—the commemoration of Jesus’ conception. Thus, Jesus was believed to have been conceived and crucified on the same day of the year. Exactly nine months later, Jesus was born, on December 25.

This idea appears in an anonymous Christian treatise titled On Solstices and Equinoxes, which appears to come from fourth-century North Africa. The treatise states: “Therefore our Lord was conceived on the eighth of the kalends of April in the month of March [March 25], which is the day of the passion of the Lord and of his conception. For on that day he was conceived on the same he suffered.” Based on this, the treatise dates Jesus’ birth to the winter solstice.

Augustine, too, was familiar with this association. In On the Trinity (c. 399–419) he writes: “For he [Jesus] is believed to have been conceived on the 25th of March, upon which day also he suffered; so the womb of the Virgin, in which he was conceived, where no one of mortals was begotten, corresponds to the new grave in which he was buried, wherein was never man laid, neither before him nor since. But he was born, according to tradition, upon December the 25th.”

In the East, too, the dates of Jesus’ conception and death were linked. But instead of working from the 14th of Nisan in the Hebrew calendar, the easterners used the 14th of the first spring month (Artemisios) in their local Greek calendar—April 6 to us. April 6 is, of course, exactly nine months before January 6—the eastern date for Christmas. In the East too, we have evidence that April was associated with Jesus’ conception and crucifixion. Bishop Epiphanius of Salamis writes that on April 6, “The lamb was shut up in the spotless womb of the holy virgin, he who took away and takes away in perpetual sacrifice the sins of the world.” Even today, the Armenian Church celebrates the Annunciation in early April (on the 7th, not the 6th) and Christmas on January 6.

Thus, we have Christians in two parts of the world calculating Jesus’ birth on the basis that his death and conception took place on the same day (March 25 or April 6) and coming up with two close but different results (December 25 and January 6).

So, there you have it- the reason why we today celebrate Jesus' birth on December 25. Merry Christmas!