The fulfillment of over 300 Old Testament prophecies of the Messiah started with Christmas.
As you can see above, these predictions included (i) the time of His birth being before the Jewish people lost their sovereign power to 1st Century Rome when Archelaus took the throne in Israel; (ii) Bethlehem, a small insignificant town, being the place of His birth; and (iii) that He would be born of a virgin.
Accordingly when the doctors of the Church perceived that the Christians had a leaning to this festival, they took counsel and resolved that the true Nativity should be solemnised on that day." Even though the quote comes from an Eastern Orthodox bishop, many Western Fundamentalist groups seized upon it in the late 19th century because it fit their anti-Catholic narrative.
The only problem here is that the good bishop, as wise as he may have been on many other issues, was just plain wrong about this one.
The first authoritative reference to the Slavs and their mythology in written history was made by the 6th century Byzantine historian Procopius, whose Bellum Gothicum described the beliefs of a South Slavic tribe that crossed the Danube heading south in just two days.The Christmas celebration of Christ’s birth on December 25th has long been a tradition of professing Christians.But when did the Church begin celebrating this day as the birthday of Christ?Therefore, all their original religious beliefs and traditions were likely passed down orally over the generations, and basically forgotten over the centuries following their rapid conversion into Christianity (which began with the conversion of Bulgaria in 864 and was largely complete by the late 11th century.) Before that, sparse records of Slavic religion were mostly written by non-Slavic Christian missionaries.Archaeological remains of old Slavic cult images and shrines have been found, though little can be yielded from them without legitimate knowledge of their contexts, other than confirming existing historical records.