The date of Christmas was not determined by Church Fathers by copying the date of a pagan Roman winter solstice festival. Instead, the date was calculated from the Jewish calendar using the date of Yom Kippur, the Day of Atonement, September 22nd, 6 BC, when Gabriel appeared to Zecharias in the Temple according to Luke 1:5. The conception of John occurred “immediately after that” when Zecharias returned home to Elizabeth to the hill country of Judea, by calculation on September 24th, 6 BC.

The conception of Jesus was calculated to have occurred when Elizabeth was “in her sixth month” (Luke 1:26,36) on March 25th, 5 BC, which was also the first day of Passover in that year. John’s birth was June 24th, 5 BC, followed by Jesus’ birth in Bethlehem on December 25th, which was also the first day of Hanukkah, or the Festival of Lights, in that year. The Church Father, Hippolytus of Rome, in his work Chronicon, saw that each date had allegorical significance.

So why is Christmas celebrated on December 25th?

The usual answer to this question is that it was adjusted, like many Church feast days, to coincide with the pagan feast days, this one being the winter solstice. This is a convenient explanation, but the exact date of December 25th is for another reason entirely. It was proposed by several of the Church Fathers at least as early as the second century. Since the “celebration of Christmas” was a custom instituted later, the second century is far too early for the “pagan copycat” thesis to be valid. To explain how the Church Fathers arrived at this date, we need to examine first the date of John the Baptist’s conception as told in Luke.

There was in the days of Herod, the king of Judea, a certain priest named Zecharias, of the division of Abijah (Luke 1:5).

According to 1 Chronicles 24:7-19, King David had divided the priests into 24 divisions who took turns serving in the Temple. During their service they lived in the Temple and were separated from their wives and children. Each order served for a period of eight days twice a year. The priests of the course of Abijah served during the 10th and 24th weeks of the Jewish year. Luke goes on to recount how the angel Gabriel appeared to Zecharias while he was serving in the Temple.

So it was, that while he was serving as priest before God in the order of his division, according to the custom of the priesthood, his lot fell to burn incense when he went into the temple of the Lord. And the whole multitude of the people was praying outside at the hour of incense. Then an angel of the Lord appeared to him, standing on the right side of the altar of incense. And when Zecharias saw him, he was troubled, and fear fell upon him.

But the angel said to him, “Do not be afraid, Zecharias, for your prayer is heard; and your wife Elizabeth will bear you a son, and you shall call his name John. And you will have joy and gladness, and many will rejoice at his birth. For he will be great in the sight of the Lord, and shall drink neither wine nor strong drink. He will also be filled with the Holy Spirit, even from his mother’s womb. And he will turn many of the children of Israel to the Lord their God. He will also go before Him in the spirit and power of Elijah, to turn the hearts of the fathers to the children, and the disobedient to the wisdom of the just, to make ready a people prepared for the Lord” (Luke 1:8-15).

Note here that “the whole multitude of the people” (i.e., the whole nation of Israel) was present outside the Temple. Some have attempted to reconstruct the weeks of service according to Josephus’ account in Antiquities 7:14:7, which relates that the first division, the division of Jehoiarib, was on duty when Jerusalem was destroyed on August 5th, AD 70. Using this date as an anchor, the eighth division of Abijah would serve two times in the year, one of them being in late September. However, it is uncertain if these allotments began on exactly the same day of the year, since there would be four extra weeks to account for at the end of the year. But there were only two times in the year when the “whole multitude of the people” of Israel was required to be in Jerusalem worshiping at the Temple. These were the fall and spring feast days. Zecharias’ vision apparently occurred on one of the high feast days, several of the Church Fathers thought it was the Day of Atonement, and then Zecharias returned to his home immediately after that.

So it was, as soon as the days of his service were completed, that he departed to his own house. Now after those days his wife Elizabeth conceived (Luke 1:23,24).

Since “the hill country of Judea,” where Elizabeth lived according to Luke 1:39;65, is no more than a day’s journey from Jerusalem, the conception of John the Baptist must have occurred soon after that. Several of the Church Fathers noticed this correspondence and made the inference that John must have been conceived shortly after the Day of Atonement, which usually falls in September. In fact, the Church Father John Chrysostom thought that Zecharias was actually the Jewish High Priest because he was in the Holy Place on the Day of Atonement, which in 6 BC fell on September 22nd. So September 24th was calculated as the date of John’s conception. The birth of John occurred exactly nine months later on June 24th.

Since Jesus was conceived six months after John (Luke 1:26,36), various dates around this time, December 25th, January 2nd and 6th were given by various Church Fathers and each of these have been celebrated as the Nativity of Jesus. In fact, the Eastern Orthodox Church has always used January 6th or 7th as the date of Christmas.

If John was conceived during one of the spring feasts — Passover or Pentecost, which were the other two times in the year when the “whole multitude of the people” of Israel was required to be in Jerusalem — then we would have a winter birth for John and a summer birth for Jesus.

Notwithstanding, the Day of Atonement fits well as an anchor date because it points to a winter birthday for Christ. Josephus notes that Herod died shortly before the Passover in 4 BC, which began on April 11th of that year. This gives several months for the events surrounding the Nativity and fits the narrative accounts of both Matthew and Luke.

We should not be dogmatic about the exact day. However, we can use December 25th as the anchor date. This date helps explain several events recorded in the Nativity accounts and is important for establishing a timeline that supports the historicity of the Gospels.