In the New Testament, there is no mention of Christmas celebrations and the first historically recorded recognition of the day was in Rome on December 25, 336 AD.
Because of a prophecy foretelling Jesus Christ and the Romans marked the winter solstice on December 25, this day was picked up as His birth date,
"But for you who fear my name, the sun of righteousness shall rise
with healing in its wings" (Malachi 4:2).
The early Christians and the Jews mocked the pagan tradition of birthday celebrations which makes it impossible to determine the precise day of Jesus' birth.
The term, Anno Domini or “AD” was introduced in 525 by the monk Dionysius Exiguous. Catholic scholar, Louis Gillet, believes that Dionysius arbitrarily attributed the birth of Jesus to December 25, 754 year from the founding of Rome and that "his calculation is devoid of historical basis."
The course of Dionysius's thoughts and logic regarding his calculation is clear. The Evangelist Luke reports the beginning of John the Baptist’s ministry began in the 15th year of the reign of Tiberius Caesar (Luke 3:23); therefore, knowing the year of the beginning of the reign of Tiberius (AD 14), Dionysius attributed the beginning of John's public teaching to 29-30 years AD.
Based on this, the year of birth of Jesus was correctly calculated. Unfortunately, Dionysius did not take into account the date of death of King Herod the Great, which is known from the writings of Josephus Flavius, namely - 4 BC and respectively, 750 years from the founding of Rome. The Gospels of Luke and Matthew unanimously state that Jesus was born "in the days of Herod the king". Jesus was probably born no later than 4 BC, most likely between 4-6 BC.
In Bethlehem, Christmas is celebrated three times a year. First by the Catholic and other Western denominations of Protestants, Anglicans and evangelical Christians on December 25, according to the Gregorian calendar. On January 7 the Eastern Orthodox Church including Greek, Russian, Romanian and others hold their celebration, according to the older Julian calendar. Finally, Jerusalem's Patriarchate of the Armenian Apostolic Church observes Christmas on January 19.
From a historical perspective the date and origins of Christmas remain obscure. The celebrations of this holiday are often strongly condemned by religious communities because of drunkenness and other misbehavior associated with it. There is also concern regarding the commercialization of the entire Christmas and Happy New Year season. Still, devout believers remember the true meaning of Christmas, no matter when it historically occurred because it signifies the coming of The Savior and long-expected Messiah into the world.
Merry Christmas!