Continuing from previous discussion about the date of Christmas, let us take a look into another hypothesis that has been in the scholarly literature for some time but hasn’t been receiving the same popular treatment as the Sol Invictus connection. The idea here has one feature all on its own that makes it attractive, that being that it will explain both the Dec 25 as well as the Jan 6 date for Jesus’ birth in various traditions. It can even explain some of the other dates noted by Clement of Alexandria at the beginning of the 3rd century (as discussed before). And it’s all about the numbers and another important day in Christendom.
To find the birthday, consider the day Jesus is supposed to have died. As the canonical Gospels tell, Jesus dies on a Friday around Passover (the Gospels disagree on what day of Passover week it was). The Passover itself requires calculation to determine. The Jewish calendar is supposed to be set such that the Passover happens on a full moon, and the first full moon after the vernal equinox is supposed to be the date of Nisan 15, Passover. The vernal equinox sets the first day of string, and in antiquity it was about March 25. By the turn of the third century, Tertullian (Adversus Judaeos 8) tells us that Jesus was crucified on Nisan 14, which he specified further with the year via Roman consuls and a date in the Roman calendar, the 8th day before the Kalends of April, that is the first day of April. The back calculation gives us March 25, the vernal equinox, as the date Jesus died.
Now, why does this matter for figuring out when Jesus was born? There appears to be a Jewish traditional belief that the date of a person’s birth was also that of their death. This is apparently the running assumption in an argument found in the Talmud between rabbis Joshua and Eliezer about the date of Creation and thus the date of the New Year (Rosh Hashanah 10-12). One would think that this means the Christians, following in this tradition, would place Jesus’ birth on March 25 instead. However, we have sources that place the Annunciation to Mary and the conception of Jesus to that March date (1). Nine months later and you get Dec 25.
What about Jan 6 as is traditional in some eastern churches? Again, ancient sources tell of Jesus’ death coming on the Macedonian calendar month of Xanthicus, specifically Xanthicus 14. This lines up with the Jewish calendar as well so that Nisan 14 runs with Xanthicus 14. That date on in 30 CE would be April 6. If the same Annunciation tradition follows here, then Jesus would be conceived on April 6 and born Jan 6. In fact we do know that this tradition existed for Jewish Christians. From the fourth century, Epiphanius says the Annunciation to Mary happened on Nisan 10 when the lambs for the Passover are shut up, which Epiphanius says symbolizes the Lamb of God being shut up into Mary’s womb (2). That date does line up with April 6, depending on the year (it works for 27 CE for example). Also from about the same time, John Chrysostom says the Annunciation happened in Xanthicus (3).
Now, these sources for connecting the conception and death dates of Jesus are late and among different sources, and none of it connects Jesus’ birth and his death date as Jewish custom had it. However, one thing that hasn’t been noted in the scholarly literature best I can tell is the same information from Clement (Stromata 1.21.145-6) about the various calculations of when Jesus was born and we he died. There Clement said that some had believed Jesus was crucified (using an Egyptian calendar) on Pharmuthi 25 (April 21), and some claimed Jesus was born on either Pharmuthi 24 or 25 (April 20 or 21). Clement doesn’t say it’s the same people making these claims, but here we do have a birth day lining up with the date of the Crucifixion. There is some reason to also think that the Nov 18th date Clement gives for his own calculation of when Jesus was born was using the old Egyptian calendar rather than the reformed one with leap years, and instead we find that Clement thought Jesus was born on Jan 6 (4).
So why was the spring birth day moving to winter and replaced by the Annunciation date? There appears to be one more piece of data that the Christians must have added into their calculations that forced the move: the birth of John the Baptist. According to Luke 1:26, John and Jesus’ conception took place six months apart. Luke’s Gospel suggest that John was conceived at or around the time of Yom Kippur which takes place on Tishri 10 (September-October). Six months later Mary gets “knocked-up” by the Holy Spirit, which would roughly get us to March or April. No way was allowed for Jesus to be born so early in a pregnancy, so I would suggest this caused the move. Now Jesus was not alleged to have been born on the vernal equinox (March 25), but was instead conceived. Thus, Jesus is born nine months later, December 25.
So, there you have a working hypothesis that has been tried for at least a century: some calculations and an odd tradition that dies birth and death dates. I cannot say that this is the mainstream view, especially since most think the Dec 25 date is based on Sol Invictus still, but there are proponents. The case is argued here by another scholar. Scholars such as Susan Roll give the hypothesis credence but note difficulties (5). However, the main difficulty (why the change from birth to conception on March 25) is something I think I have an answer for. We may really be closer to the correct hypothesis than we realize.
Now, I noted at the end of my first post on the date of Christmas was that this would illustrate how the Christian story of Jesus’ life was mostly myth. You can probably see how some traditions could be set using retrojected speculations of when what happened based on non-historical thinking, but how does that undermine anything more than just when Christmas is celebrated? That I shall save for another post. However, as a bit of a spoiler, I will say it has to do with more back calculations. Stay tuned!
(1) Thomas Talley, Origins of the Liturgical Year, p. 94 (quoting De Solstitiis, a fourth-century North African work); Augustine, Questionum in Heptateuchum 2.90; De Trinitate 4.5.
(2) Talley, op. cit., pp. 97-9.
(3) Jacques Paul Migne, Patrologia Graeca 49.351-62.
(4) Talley, op. cit., p. 119.
(5) Susan Roll, “The Origins of Christmas: The State of the Question”, in Johnson, Between Memory and Hope (2000), pp. 288-9.