Could December 25 as the birthday of Jesus have come from Pagan influences? Could December 25 as the birthday of Jesus have come from Pagan influences? 

I am asking this due to the information in the following sources:


“NIMROD” – The LORD of
Christmas
Church of Satan Holiday FAQ


This question is asked for information to engage in solid &amp; meaningful apologetics with pantheists &amp; satanists and not to bash Roman Catholics.The comments to Caleb gives more info.
From the Bible, we can be pretty sure that Jesus was not born on December 25.

Late September or early October, perhaps even on the first day of the Feast of Tabernacles, is the most likely time.

Here is an part of an essay written elsewhere, in which I summarized the birth date:


  Though it seldom snows there, December in Jerusalem is a cold and wet time.
  From early Spring to late Fall, it was common for sheep, goats, and cattle to graze on the grassy lands in the area. But after the Fall harvest, animals would be kept close to home where they could eat hay and be sheltered at night.
  
  That any shepherds would be out in the fields, tending flocks at night in late December is very unlikely.
  
  The Bible
  
  While not explicitly condemning the practice, the Bible hardly encourages the celebration of birthdays. The few times that birthdays are mentioned, they are unpleasant events such as the presentation of John the Baptist's head as a birthday present.
  
  The Bible records the date and time of Jesus's death, but not of his birth. There are sufficient clues that one can make a reasonable estimate though.
  
  Elisabeth conceived (John the Baptist) immediately after Zacharias finished his Abia priestly duties (Luke 1):
  
  [5] ... priest named Zacharias, of the course of Abia ... [8] ... he executed the priest's office before God in the order of his course [23] ... as soon as the days of his ministration were accomplished, he departed to his own house. [24] And after those days his wife Elisabeth conceived ...
  
  Her cousin Mary conceived (Jesus) six months later:
  
  [26] And in the sixth month the angel Gabriel was sent from God unto a city of Galilee, named Nazareth [27] To a virgin espoused to a man whose name was Joseph, of the house of David; and the virgin's name was Mary.
  [36] And, behold, thy cousin Elisabeth, she hath also conceived a son in her old age: and this is the sixth month with her, who was called barren. [40] And [Mary] entered into the house of Zacharias, and saluted Elisabeth. [56] And Mary abode with her about three months ...
  
  The "course of Abia" is defined in the First book of Chronicles:
  
  [24:10] The seventh to Hakkoz, the eighth to Abijah
  [24:19] These were the orderings of them in their service ...
  
  Each priest served for a week, with the cycle beginning on the 1st day of Nisan. But during the week of Passover (Nisan 14) and Pentecost (7 weeks later) all priests served together, so Zacharias, being of the 8th course, would have finished his first course after the 10th week of the year.
  Six months after that (Jesus's conception) would have been around what the Romans called late December, and nine months after that (Jesus's birth) would have been late September or early October.
  
  That would be around the time of Sukkot (the Feast of Tabernacles).
  Sukkot is one of three times each year when people made a pilgrimage to Jerusalem. 
  In addition to the normal tithe given to support the priesthood, people were encouraged to save a second tithe to use for their own expenses and celebrations during these times
  (Deuteronomy 14:26): "And thou shalt bestow that money for whatsoever thy soul lusteth after, for oxen, or for sheep, or for wine, or for strong drink, or for whatsoever thy soul desireth: and thou shalt eat there before the LORD thy God, and thou shalt rejoice, thou, and thine household".
  
  Even today, most people that observe this fall festival travel away from home, or if they can't, they arrange to sleep in a tent or some other location different from their normal home.
  
  It's by no means a certainty that this is when Jesus was born, but if Jesus had been born during the Feast of Tabernacles, it then confirms why his parents stayed in their family's home town of Bethlehem, just south of Jerusalem.
  
  Why
  
  Roman Christianity was developed during the first few centuries after Jesus, and was largely canonicalized during the reign of Emperor Constantine.
  Though he was largely responsible for defining Roman Christianity, throughout this process Constantine remained a Sun worshipper, and didn't formally convert to Christianity until shortly before his death.
  
  One way for the official Roman religion to subsume the many existing religions and cults, both in Rome and throughout the Empire, was for it to incorporate their more popular practices while requiring nothing more than that the names be changed.
  A single universal religion, regardless of what it believed, would make the Empire stronger and easier to control.
  
  If people wanted to continue to celebrate December 25, whether in honour of Mithras or of the Sun God Apollo, they could continue to do so, just so long as they now call him Jesus.