The date of December 25th was chosen as the day to celebrate Christmas because it is believed to be the day of Jesus Christ's birth. The exact date of Jesus' birth is unknown, but the early Christians chose December 25th as the day to celebrate his birth in order to align it with the Roman holiday of Saturnalia, which was celebrated around the same time. It was also the day when the sun began to rise a bit earlier and the days began to get longer, so it was seen as a symbol of new beginnings and hope.