Jesus of Nazareth or Jesus Christ, was born on December 25 of year 0 (even if due to errors in the calculation of the years that occurred during the history, it would prove today that the true date of birth is in -5 or -7 BC).
Every year Christians around the world come together to celebrate the coming of Christ the Savior on Christmas Day. This celebration is one of the most important for the Christian community but what about before the year zero?
Before the birth of Christ, December 25 was the day of celebration of the sun, and more exactly of the birth of the sun. Indeed, in the 3rd century AD, the Roman Empire went through a great period of internal troubles. In terms of religion the Roman Empire was very desperate, there were many local cults and each had their own celebrations.
In an effort to gather and to give everyone a feeling of belonging to the empire, the emperor Aurélien established a big party which was to be observed on all the imperial territory, that of the "Sol invictus" (the invincible sun). The date of “Sol invictus” was fixed on December 25th, which at that time corresponded to that of the winter solstice. The winter solstice, which is the shortest day of the year became the day of celebration with circus games of the "day of birth of the sun" (dies natalis soli invicti in Latin).
This cult spread rapidly throughout the empire, thanks to the army, making it an important religious holiday. On March 7, 321, Emperor Constantine I, a great follower of the "Sol invictus", promulgated a law that made the "day of the sun" the weekly rest day. This is how the name "Sunday" derived (Sun Sun and Day Day) in English or "Sonnestag" (Sun Sound and Day Tag) in German.
It was then during the Christianization of the Roman Empire in the fourth century that the cult of the "Sol invicitus" gradually became replaced by syncretism * by that of the birth of Jesus Christ. A first step was taken in 354 when the Christians of Rome decided to celebrate the birth of Christ on the same date and it was finally the emperor Theodosius I who promulgated the Edith of Thessaloniki in 380, which prohibited the cult of "Sol invictus and made December 25 an exclusively Christian holiday.
(ETYM : Anciant greek συγκρητισμός, (sugkrêtismós,)
sing-kri-tiz-uh m, sin the attempted reconciliation or union of different or opposing principles, practices, or parties, as in philosophy or religion.