December 25 has been celebrated since the beginning of Christianity as the birthday of Christ, although originally on this date the “return of the sun” was celebrated – the first day when the sun shines on the earth a little longer than the previous day.
December 25 was chosen to celebrate the Christian Christmas in order to compete with the cult of the light god Mithras, popular in Rome at the beginning of Christianity, whose rebirth was celebrated on the winter solstice.
According to biblical scholars, Christ was born six months before Easter, at a time when it was warm enough in Israel for shepherds and their livestock to sleep in the fields, as described in the birth story of Jesus in the Bible, so in September or October. This fact further supports the assumption that already in the very beginnings of Christianity, just like today, there were popular efforts to integrate Christian and pagan traditions.
However, Christian traditions are also different on this day – according to Catholic traditions, the Christmas feast after the fast observed during Advent is held on December 25, while in Protestant traditions, the guests are feasted the day before – on the evening of December 24.