To the militant athiests from this thread....

History
For many centuries, Christian writers accepted that Christmas was the actual date on which Jesus was born.[46] However, in the early eighteenth century, scholars began proposing alternative explanations. Isaac Newton argued that the date of Christmas was selected to correspond with the winter solstice in the northern hemisphere,[9] which in ancient times was marked on December 25.[47] In 1743, German Protestant Paul Ernst Jablonski argued Christmas was placed on December 25 to correspond with the Roman solar holiday Dies Natalis Solis Invicti and was therefore a "paganization" that debased the true church.[8] In 1889, Louis Duchesne suggested that the date of Christmas was calculated as nine months after the Annunciation (March 25), the traditional date of the Incarnation.[48]

Christian establishment

There is no evidence scripturally or secularly that early Christians in the first century commemorated the birth of Jesus Christ. In fact, in keeping with early Jewish law and tradition, it is likely that birthdays were not commemorated at all. According to The World Book Encyclopedia: "early Christians considered the celebration of anyone's birth to be a pagan custom." (Vol. 3, page 416) Rather than commemorating his birth, the only command Jesus gave concerning any sort of commemoration of his life actually had only to do with his death (Luke 22:19). It was not until several hundred years after the death of Jesus Christ that the first instances of the celebration of Christmas begin to appear in the historical record. According to the new Encyclopedia Britannica, some who later claimed to be Christian likely "wished the date to coincide with the pagan Roman festival marking the 'birthday of the unconquered sun'." The festival was celebrated with similar customs (gift giving, feasting) that are done to celebrate Christmas today.

The New Testament does not give a date for the birth of Jesus.[6][55] Around AD 200, Clement of Alexandria wrote that a group in Egypt celebrated the nativity on Pachon 25.[6] This corresponds to May 20.[56] Tertullian (d. 220) does not mention Christmas as a major feast day in the Church of Roman Africa.[6] However, in Chronographai, a reference work published in 221, Sextus Julius Africanus suggested that Jesus was conceived on the spring equinox, popularizing the idea that Christ was born on December 25.[57][58] The equinox was March 25 on the Roman calendar, so this implied a birth in December.[59] De Pascha Computus, a calendar of feasts produced in 243, gives March 28 as the date of the nativity.[60] In 245, the theologian Origen of Alexandria stated that, "only sinners (like Pharaoh and Herod)" celebrated their birthdays.[61] In 303, Christian writer Arnobius ridiculed the idea of celebrating the birthdays of gods, which suggests that Christmas was not yet a feast at this time.[6]

Incorrect birth date of Jesus

Followers of the Jewish and Messianic religions have said that Jesus was born during or around the festival of Sukkot (which occurs between early September and early October every year), not in December.[60] There is also controversy concerning the precise date of December 25 as the birthday of Jesus. In certain religions and myths, the 25th of December is the day assigned to the celebration of various sun gods. Most notably, Sol Invictus ("The Unconquerable Sun"), originally a Syrian god that was later adopted as the chief god of the Roman Empire under Emperor Aurelian, is traditionally celebrated on the 25th of December, as are several gods associated with the winter solstice in many pagan traditions.[61] However, it is possible that December 25 was simply set aside for celebration by Christians, since Jesus' exact birthdate is unknown.