when was the first christmas day

The first Christmas day is believed to have been celebrated by Christians on December 25th, 336 AD. This date was chosen to commemorate the birth of Jesus Christ, who Christians believe is the Son of God. Prior to this, the ancient Romans celebrated their winter solstice festival on December 25th, but it was not a religious observance. The date of Christmas was later established as a holiday by the Catholic Church in the fourth century AD.