No Christian text does not specify what day of the year was born Jesus Christ. Christmas is not part of the celebrations followed by the early Christians and is not included in the lists published by Irenaeus and Tertullian. Given that, according to biblical accounts of Christmas, the herds are out with their shepherds, so we can deduce that Jesus’ birth was certainly not located in the winter. In the fourth century, the date of December 25 was chosen as the date for the Christmas party, mainly to replace the pagan holidays that were in use at the time, as the feast of the rebirth of the Undefeated Sun (”Sol Invictus”), the winter solstice and the Roman Saturnalia, which had all held in the period from December 25. the oldest document mentioning the date of December 25 is the Chronograph of 354 (referring to book reviews dating back at least to 336).
Long before the advent of Christianity, the time of the winter solstice was already a turning of the year, which included many pagan beliefs regarding fertility, motherhood, procreation and astronomy. It thus gave rise to many events. These ancient traditions have many points of similarity with the Christian festival.
Near Eastern antiquity
Some traditions and symbols associated with the Christian Christmas are attested in other religions that preceded Christianity: day of the year chosen by the church, the cave, the shepherds.
In the Mithraic cult, the largest party – the Mithragan – taking place every year on the day of the winter solstice, the day celebrating the birth of divinity and the victory of light over darkness. In a Mithraic tradition born in Asia Minor, Mithra was born “gushing from the rock” or a cave – element eminently linked to the worship of that deity – while shepherds attending this miraculous birth in a story that will influence those of the birth of Jesus to suit the pagan themes. It is possible that an older tradition of mithraïc and Mazdean origin, with the mother of Mithra – Anahita (or Anahid) – as a virgin, has also influenced the early Christian writers.
In the celebrations of Mithraic worship, strongly developed in the Greco-Roman empire in the third and fourth centuries, December 25 corresponded to the celebration of Natalis Invicti, the birth of the unconquered sun, who gets his strength and give back the day against the night .
In Judaism, the hanukkah celebration, which commemorates the rededication of the Jerusalem Temple desecrated by the ancient Greeks, was set to 25 of the ninth lunar month called Kislev (Hebrew calendar) in the vicinity of the winter solstice. The first book of Maccabees stresses the importance of this day and this celebration.
Traditional representations of the Virgin and Child (theme on the childhood of Jesus and not to its single birth) it is possible to draw their origins in the representations of the Egyptian goddess Isis nursing the Horus child.
In ancient Rome, the citizens celebrated the Saturnalia: first of December 17 to 21, and later of December 17 to 24, men and women wore garlands around his neck and offered all kinds of gifts. People symbolically sacrificed a mannequin representing a young man, thinking convey the vitality of the character in the new year. Note that fixing the date of December 25, the winter solstice is due to an error made by the astronomer Sosigenes of Alexandria, during the calendar reform initiative of Julius Caesar in 46 BC, which fixed the start of the season with a delay of one or two days over the real date.
The feast of sigillaria, “ancestor” of New Year’s Eve, concluded the festivities at the end of December. Meanwhile this toggle to the new year, people were offering gifts of terracotta, slaves became the masters and vice versa.
Starting with the reign of Aurelian (270-275), the Romans officially celebrate the Sol Invictus (the unbeaten Sun) at the time of the winter solstice which began the new year, announced by the lengthening of the days. This cult, which incorporates aspects of the mythology of Apollo and the cult of Mithra, has spread to the fourth and third centuries BC and ended with the sacrifice of a bull, the Sol Invictus corresponding to the birth of the young sun god who, echoing the traditions mithraïques, was supposed to arise from a rock or a cave in the form of a newborn child.
(Translated from Wikipedia)