Why Do We Celebrate Christmas on 25 December?
In the first century the Church did not celebrate the birth of Christ. It is important to remember that in the very first few years of the Church, the only feast days being celebrated were those to do with the death and resurrection of Christ: that is, Pascha. After a few decades the Church desired to also celebrate the Epiphany of our Lord on 6 January. This meant celebrating the fact that God took on human form and visited us: “God is the Lord and has revealed Himself to us!” Later the Church decided to break up the Epiphany feast into its components: the birth, baptism, the circumcision and the entering into the temple. These commemorations were each given different dates and you can be sure there was a lot of debate about the dates. In some parts of Christendom the feast of Christmas was celebrated on 6 December, while in other parts it stayed on 6 January. Eventually the majority of Christian bishops agreed to celebrate on 25 December. Interestingly, the Armenian Orthodox Church, which broke away from the Universal Church in the fourth century and thus did not change its practice of celebrating Christmas, still celebrates Epiphany as a combined commemoration of the birth and baptism of Christ, just as the Church did in the 2nd – 3rd century.
The actual date of the birth of Jesus Christ is unknown. No date is given in the Bible, only some hints according to certain historical events that happened at that time. In those days, birthdays were not recorded, nor were they considered important. Most people measured their ages by making a connection to a historical event. For example, they would say: “Mark was born during the reign of Tiberius” rather than on a particular date. So the birth date of Jesus was most probably never recorded. If the Church was to celebrate Christmas, they would have to select a date.
The earliest known indication of a celebration of Christmas comes in a passing statement by St Clement of Alexandria who mentions that the Egyptians of his time celebrated the Lord’s birth on 20 May. At the end of the 3rd century, many Churches celebrated it in the winter, and this was only accepted in Rome in the middle of the 4th century. The first recorded date of Christmas being celebrated on December 25th was in 336AD, during the time of the Emperor Constantine (306-337). A few years later, Pope Julius I officially declared that the birth of Jesus would be celebrated on the 25th December.
There are several theories surrounding the question as to why 25 December was chosen as the day to celebrate the nativity of our Lord. One theory is that 25 December was chosen to Christianise the pagan festival which some Christians were still celebrating, even as late as the 4th Century. This festival was the “birthday of the unconquered sun” which was a celebration of the sun god at the time of the winter solstice.
Another theory is that the 25 December is exactly nine months from the Annunciation by Archangel Gabriel to the Virgin Mary that she would give birth to Christ. 25 March had already been chosen by the Church and it was only natural to put Christmas nine months later.
December 25th might have also been chosen because the Winter Solstice and the ancient pagan Roman midwinter festivals called ‘Saturnalia’ and ‘Dies Natalis Solis Invicti’ took place in December around this date. It was also the time of the Jewish festival of lights called Hanukkah. So, it was a time when people already celebrated things and it was good to give a Christian focus in that period of the year.
By the end of the fourth century, most Church jurisdictions all over the known world had agreed to celebrate the nativity of our Lord Jesus Christ on 25 December.
Around the 1920s the Orthodox Churches around the world decided to move from the Julian Calendar to the Gregorian Calendar, because the Julian Calendar was mathematically flawed and was thirteen days behind. When the calendar change was made, some jurisdictions such as Moscow, Serbia and Mount Athos, were given the blessing to stay on the “Old Calendar”. As a result these churches remain 13 days behind. This means that churches still on the Julian calendar celebrate Christmas on 6 January and they celebrate Epiphany on 19 January
Source: Lychnos December 2016 / January 2017