Christmas is celebrated worldwide on December 25th and commemorates the birth of Jesus Christ. Although the precise origin of the date is unclear, Sextus Julius Africanus first talked of the the event in 221.
The word Christmas (“mass on Christ’s day”) was not always used and is of fairly recent origin. In the olden days people reffered to the day as Yule, most likely derived from the Germanic jōl or the Anglo-Saxon geōl, which referrs to the winter solstice feast.