Let’s begin with two accepted facts. 1) we do not know the exact date on which Jesus was born; and 2) many elements of pre-Christian festivals have found their way into Christian holy days. But that leads us to another fact: contrary to popular belief, the Christian church did not plan to erase the pagan feast of Saturnalia when it proclaimed December 25 as the birth of Christ.
The early Christian church did not celebrate Jesus’ birth. Although it wasn’t until A.D. 440 that the church officially recognized December 25, St. Theophilus, the bishop of Caesarea (AD 115-181), said the birthday of Jesus should be celebrated “on what day so ever the 25th of December shall happen.” Saturnalia commemorated the winter solstice, which falls on December 22. It was celebrated as early as December 17 and extended until December 23, so the date doesn’t even match.
It is true that some of our modern Christmas traditions, such as decorating a Christmas tree, can be considered throwbacks to these pre-Christian times. In fact, the apostles predicted that some Christians would adopt pagan beliefs to enable them to blend in with the pagans around them.
But the early church had put much more thought into selecting the date. They pieced together a puzzle, based on the Gospels, oral tradition, a second century document called Protoevangelium of Saint James and Catholic theologian Josef Heinrich Friedlieb.
They began with John the Baptist, who was six months older than Jesus. We know this from Luke 1:26, which tells us that Elizabeth was six months pregnant at the time of the Annunciation. From here, they gathered all the facts they could.
Zechariah, John’s father, was a priest of the class of Abijah (Luke 1:5). This was the eighth class of twenty-four priestly classes (Nehemiah 12:17). Each of those eight classes served in the temple for one week, twice every year. Friedlieb established that the course of Abijah served during the eighth week and the thirty-second week in the annual cycle. This means that Zechariah would have been on duty during the second week of the Jewish month of Tishri, which falls between September 22 and 30. The Protoevangelium of Saint James places him on duty at the temple during the Day of Atonement on the tenth day of Tishri. It was while he was on duty that the Angel Gabriel told him that he and Elizabeth would be having a child (Luke 1:5-24).
Allowing for a 40-week pregnancy, John would have been born toward the end of June, hence the church’s commemoration of his birthdate on June 24.
Add six months, and we get December 24, Christmas Eve. We know from the Scriptures that Jesus was born at night, so December 25 would be the date of His birth. This is also why the church recognizes March 25 and the date of the Annunciation.
So, are we certain of the December 25th date? Not at all. But we are certain that those who try to discredit Christianity with their stories of Saturnalia are misinformed.