Christmas originally Christ's Mass was not celebrated in the first 300 years of Christianity and after that different churches celebrated it on different dates,
The Bible offers few clues: Celebrations of Jesus’ Nativity are not mentioned in the Gospels or Acts; the date is not given, not even the time of year. The biblical reference to shepherds tending their flocks at night when they hear the news of Jesus’ birth (Luke 2:8) might suggest the spring lambing season; in the cold month of December, on the other hand, sheep might well have been corralled. Yet most scholars would urge caution about extracting such a precise but incidental detail from a narrative whose focus is theological rather than calendrical.
The extrabiblical evidence from the first and second century is equally spare: There is no mention of birth celebrations in the writings of early Christian writers such as Irenaeus (c. 130–200) or Tertullian (c. 160–225). Origen of Alexandria (c. 165–264) goes so far as to mock Roman celebrations of birth anniversaries, dismissing them as “pagan” practices—a strong indication that Jesus’ birth was not marked with similar festivities at that place and time.1 As far as we can tell, Christmas was not celebrated at all at this point.
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How December 25 Became Christmas – Biblical Archaeology Society
Christmas as we now know it did not become established until the 1800s
The German people had an enormous part to play in shaping Christmas into the form we know and love today. One of the beneficiaries of the German love of Christmas was Victorian England. Victoria assumed the throne in 1837 at the age of eighteen; three years later she married Prince Albert who became Prince Consort. Prince Albert, being of German descent, brought with him to England many of the wonderful Christmas traditions of his homeland. Christmas soon became a special occasion for the Royal Family; their celebration of it emphasized the importance of family closeness and an appreciation of children, and revived the idea of the holiday meal and holiday decorations. In 1841 Prince Albert introduced the first Christmas tree to Windsor Castle; he was largely responsible for the later popularity of Christmas trees in England. Since Victoria and her family held an astonishing popularity with the British, much of what they did was widely emulated. Newspapers and magazines such as The Illustrated London News provided a ready audience with chronicles of the royals' activities. Anything seen in the castle was soon copied in homes throughout the country, providing the English Christmas with a much-needed boost.
Gradually, over the course of Victoria's reign, the tide turned. Christmas once more had an important place in English life.
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December 25 Wasn't the First Choice for Christmas Day | Lone Star's Christmas Connection
Over all there is no historical or biblical record as to when Jesus(as) was born