Christmas or Christmas Day is a holiday observed generally on December 25 to commemorate the birth of Jesus, the central figure of Christianity. The date is not known to be the actual birthday of Jesus, and may have initially been chosen to correspond with either the day exactly nine months after Christians believe Jesus to have been conceived, the date of the Roman winter solstice, or one of various ancient winter festivals.Christmas is central to the Christmas and holiday season, and in Christianity marks the beginning of the larger season of Christmastide, which lasts twelve days. [source]