** It’s not until the 12th century that we find the first suggestion that Jesus’ birth celebration was deliberately set at the time of pagan feasts.** A marginal note on a manuscript of the writings of the Syriac biblical commentator Dionysius bar-Salibi states that in ancient times the Christmas holiday was actually shifted from January 6 to December 25 so that it fell on the same date as the pagan Sol Invictus holiday. In the 18th and 19th centuries, Bible scholars spurred on by the new study of comparative religions latched on to this idea. They claimed that because the early Christians didn’t know when Jesus was born, they simply assimilated the pagan solstice festival for their own purposes, claiming it as the time of the Messiah’s birth and celebrating it accordingly.
More recent studies have shown that many of the holiday’s modern trappings do reflect pagan customs borrowed much later, as Christianity expanded into northern and western Europe. The Christmas tree, for example, has been linked with late medieval druidic practices. This has only encouraged modern audiences to assume that the date, too, must be pagan.
There are problems with this popular theory, however, as many scholars recognize. Most significantly, the first mention of a date for Christmas (c. 200) and the earliest celebrations that we know about (c. 250–300) come in a period when Christians were not borrowing heavily from pagan traditions of such an obvious character.
Granted, Christian belief and practice were not formed in isolation. Many early elements of Christian worship—including eucharistic meals, meals honoring martyrs and much early Christian funerary art—would have been quite comprehensible to pagan observers. Yet, in the first few centuries C.E., the persecuted Christian minority was greatly concerned with distancing itself from the larger, public pagan religious observances, such as sacrifices, games and holidays. This was still true as late as the violent persecutions of the Christians conducted by the Roman emperor Diocletian between 303 and 312 C.E.
This would change only after Constantine converted to Christianity. From the mid-fourth century on, we do find Christians deliberately adapting and Christianizing pagan festivals. A famous proponent of this practice was Pope Gregory the Great, who, in a letter written in 601 C.E. to a Christian missionary in Britain, recommended that local pagan temples not be destroyed but be converted into churches, and that pagan festivals be celebrated as feasts of Christian martyrs. At this late point, Christmas may well have acquired some pagan trappings. But we don’t have evidence of Christians adopting pagan festivals in the third century, at which point dates for Christmas were established. Thus, it seems unlikely that the date was simply selected to correspond with pagan solar festivals.