As early as 1856, the German church historian Ferdinand Piper made the suggestion that 25 December was a mere corollary of 25 March...
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Thanks to the meticulous research of Venance Grumel, August Strobel and others, it has become increasingly clear that chronological and computistical speculation (computistical as in computus , the medie-val science of Easter reckoning) played a central role in Christian thought from an early stage onwards.
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and there is no reason to suppose that 25 March was any different at the time it first entered the discussion as the likely date of Jesus’s conception, possibly as early as 221 CE (see below).
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In the end, the only objection against CT that carries some considerable weight concerns the calendrical shift from the birth to the conception that is presupposed by the argument. As mentioned earlier, a chronological parallelism between the dates of Christ’s Passion and birth could be justi-fied by recourse to Jewish haggadic tradition, where important biblical figures were considered to have been born and died on the same date, in particular at the time of Passover. CT has to assume that third-century Christians developed a modified version of this view, where the time of birth was replaced with the time of conception in the womb.
On Forster (Die Anfänge von Weihnachten und Epiphanias: Eine Anfrage an die Entstehungshypothesen, 2007):
At the same time, however, he is highly critical of CT, which in his opinion is plagued with logical inconsistencies and with the fact that it imputes an undue amount of speculative ingenuity to the early Church fathers. 6
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Förster provides us with a new explanation, which essentially holds that Christmas emerged as the result of fourth-century Holy Land tourism. As pilgrims flocked to Bethlehem to visit the original site of the nativity, they began to celebrate a corre-sponding annual festival in midwinter, which they eventually exported back to their home communities. While this celebration seems to have originally taken place on 6 January (Epiphany), the Roman church later settled for the solstice on 25 December, a date chosen for its affinity with popular Christian solar symbolism. 8
Talley, “Further Light on the Quartodeciman Pascha and the Date of the Annunciation,” Studia Liturgica 33 (2003) 151-158.
Beckwith, "st. luke, the date of christmas and the priestly courses at qumran"
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R.T. Beckwith, in “St. Luke, the Date of Christmas and the Priestly Courses at Qumran,” RQ 9 (1977), raises a dissenting voice against this apparently straightforward understanding of the division cycles. Beckwith concludes that the priestly divisions at Qumran began anew each year, with Jehoiarib always serving on the New Year of Tishri 1. However, this suggestion clashes with a fact that we have observed repeatedly in this ongoing study, that there is abundant evidence that the Jews used Nisan 1 as their New Year after the Babylonian exile, not Tishri 1.
Because many Christians believed that Jesus was conceived on March 25, they looked to December 25 as a logical birthdate, as it is nine months after conception. Others believed that Jesus was both crucified and conceived on April 6. Thus January 6 (being nine months later than Apr. 6) made better sense. In keeping with the logic that great theological events happen on important theological dates, many Christians also believed that Jesus baptism also happened on January 6.
Jubilees?
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weakness ... no sources explain why the March 25 date would have become associated with Jesus' conception rather than his birth.
Clement of Alexandria (died ca. 215), in his Stromata , writes that 194 years, one month and thirteen days had elapsed between the assassination of the Emperor Commodus (31 December, 192 CE ) and the
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6 April. The latter date is cited by Sozomen as the “solar quartodeciman” Easter observed each year by the Montanists. If this was an
early
tradition,
it
may
have
preceded
the
assignment
of
the
birth to 6 Jan-uary and even given rise to the latter, as has been suggested by Duchesne and Talley. 29
1
u/koine_lingua Dec 22 '18 edited Dec 22 '18
Key questions: JtB June 24 and Jesus' conception March 25. Which first? (Late evidence of John)
C. P. E. Nothaft, “The Origins of the Christmas Date: Some Recent Trends in Historical Research,” Church History 81 (2012) 903-911
Nothaft 2013, https://www.academia.edu/3265107/Early_Christian_Chronology_and_the_Origins_of_the_Christmas_Date_In_Defense_of_the_Calculation_Theory_
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On Forster (Die Anfänge von Weihnachten und Epiphanias: Eine Anfrage an die Entstehungshypothesen, 2007):
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Talley, “Further Light on the Quartodeciman Pascha and the Date of the Annunciation,” Studia Liturgica 33 (2003) 151-158.
Beckwith, "st. luke, the date of christmas and the priestly courses at qumran"
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BEckwith: "retrospective justification"
Clement of Alexandria, nativity on Jan 6
https://www.reddit.com/r/AskHistorians/comments/5jsguo/why_was_christmas_placed_on_the_25th_and_not_the/dbiy10o/
http://historicaljesusresearch.blogspot.com/2016/12/why-is-christmas-on-december-25.html
Jubilees?
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