According to Dr. Kelly's research, summarized in his books
The Origins of Christmas, and
The World of the Early Christians, the main reason early Christians chose December 25th for the date of Christmas relates to two significant and symbolic dates: the date of the creation of the world, and the vernal equinox. According to some Christians, both events happened on March 25th. Early Christian writer Sextus Julius Africanus (220 AD) speculated that the world was created on March 25th, based on his chronology of Jewish and Christian history, presumably contained in his Chronographia. So he suggested that Christ became incarnate on that date; this makes perfect symbolic sense, since at the Incarnation, the new creation began. According to Julius, since the Word of God became incarnate from the moment of his conception, this meant that, after 9 months in the Virgin Mary's womb, Jesus was born on December 25. The anonymous author of the work
De Pascha Computus, likely written in the 3rd century, and attributed to Cyprian, too speculated the world was created on March 25th. However, since the sun was created on the fourth day of creation, the author speculates that Christ was
born on March 28th, not March 25th. Thus, unlike Julius, this author conceives of Christ's incarnation beginning at Christ's birth, rather than his conception. How did this anonymous author reach his conclusions about the date of creation? Based on a synthesis of the time of Passover, the vernal equinox, and a prophecy from Malachi about the "Sun of Righteousness." While the scope of the influence of Julius and the anonymous author of De Pascha Computus upon their peers is unknown, nonetheless, we encounter reasons why the date of December 25th was chosen for the birth date of Jesus that are rooted in Christian thought.
According to
Get Religion, Hippolytus of Rome, writing around 225 AD, close to the time of Julius, may also mention the date of Christmas as December 25 ("eight days before the kalends of January"), in Commentary on Daniel. However, there is debate as to whether this line is genuine, or an interpolation in the genuine text of Hippolytus. The best manuscripts of Hippolytus mention both December 25th and April 2nd as possible dates for the birth of Jesus, although the latter could refer to his conception, which would then place his birth in December. In addition to Kelly's books,
The Origins of the Liturgical Year provides much insight into the speculation discussed here.
There are other good, Jewish, Christian, and biblical reasons why Christians chose the date of December 25th. One is based on the estimated date of the death of Jesus, which some early Christians speculated happened on Friday, March 25th. Incidentally, this is historically impossible, since March 25th would not have been a Friday the year Jesus likely died. Nonetheless, based on the Jewish idea of the "integral age," that great prophets were conceived on the same date as their death, these early Christian writers thought that Jesus, who died on March 25th, was also conceived that date. Again, if we assume nine months in the womb, this means he was born on December 25th. The work
De Solstitia et Aequinoctia Conceptionis et Nativitatis Nostri Iesu Christi et Iohannis Baptistae, falsely attributed to John Chrysostom, supports this view:
Therefore our Lord was conceived on the eighth day of the kalends of April in the month of March, which is the day of the passion of the Lord, and of his conception. For on the day he was conceived, on the same day he suffered (quoted in Stuhlman, Redeeming the Time).
Scholar William Tighe makes a strong case for his theory in his essay
Calculating Christmas, which is apparently similar to arguments made by Louis Duchesne and Andre Wilmart years earlier. This line of speculation was occurring about the same time other Christians were speculating about the date of Christ's birth based on the date of creation. Perhaps this interest in December 25th among early Christians is because they were already celebrating Christmas on this date?
Yet another reason for choosing the date of December 25 is advanced by 4th century bishop and writer Saint John Chrysostom. According to
this article from the North County Times, John Chrysostom reasoned:
Luke 1 says Zechariah was performing priestly duty in the Temple when an angel told his wife Elizabeth she would bear John the Baptist. During the sixth month of Elizabeth's pregnancy, Mary learned about her conception of Jesus and visited Elizabeth "with haste."
The 24 classes of Jewish priests served one week in the Temple, and Zechariah was in the eighth class. Rabbinical tradition fixed the class on duty when the Temple was destroyed in A.D. 70 and, calculating backward from that, Zechariah's class would have been serving Oct. 2-9 in 5 B.C. So Mary's conception visit six months later might have occurred the following March and Jesus' birth nine months afterward.
Thus, for John Chrysostom, the date of December 25 was based on Scripture and Jewish tradition. While it is possible John was mistaken, this demonstrates that Christians at the time were choosing the dates of feasts based on Scripture, not paganism.
David Morrison explains yet another possibility, again providing a rationale for the choice of December 25:
The angel Gabriel appeared to Mary "in the sixth month" of the Jewish year...that is, in Adar (our February/March). Count nine months for the pregnancy and you come to Kislev (our November/December). According to some Church Fathers, Jesus was born during Channukah. Therefore, Jesus Christ was born of the Holy Virgin Mary in Bethlehem of Judaea in the Jewish month of Kislev (December) during the Festival of Lights. And I say likely on what is December 25th.
So, we have multiple reasons why ancient Christians chose December 25th as the date to celebrate the birth of Jesus. And while we may not agree with the reasoning behind the choice of December 25th, nonetheless, there are no pagan conspiracies at work, and no evil machinations of the emperor Constantine, just solid Christian symbolic reasoning. This is not surprising, considering Christians of the time were very concerned about the influence of paganism, and took great pains (even giving their lives) to avoid worshiping or celebrating non-Christian gods. Besides, virtually every historical and Apostolic Christian church celebrates the birth of Jesus on December 25 (those using the Gregorian calendar that is), and it is highly unlikely every Church in every region caved into pagan influence so readily. While all of these explanations are certainly subject to questions and certain criticisms, they certainly are worth exploring.
At this point, you may be asking, "but wasn't Christmas chosen to counter pagan festivals?" Well, yes, in a sense, but not in the same way that the anti-Christmas crowd claims. According to Dr. Kelly, Christians of the late third and early fourth centuries had been engaged in a propaganda war with pagans since the Emperor Aurelian established the
Sol Invictus, the feast of the unconquered Sun, on December 25th. For Christians, Jesus is the true Sun, the Sun of Righteousness (a title derived from Malachi 4:2). In fact, Aurelian may have established the
Sol Invictus because of the rising popularity of Christianity, and may have established the date of the
Sol Invictus in response to Christian celebrations already occurring that day! Since Christians probably accounted for ten percent of the population of Rome at the time, this is not far-fetched in the least.