Christmas is based on the story of Jesus' birth as described in the Gospel according to Matthew （see Matthew 1:18-2:12） and the Gospel according to Luke （see Luke 1:26-56）. Roman Catholics first celebrated Christmas, then known as the Feast of the Nativity, as early as 336 ad. The word Christmas entered the English language sometime around 1050 as the Old English phrase Christes maesse, meaning “festival of Christ.” Scholars believe the frequently used shortened form of Christmas-Xmas-may have come into use in the 13th century. The X stands for the Greek letter chi, an abbreviation of Khristos （Christ）, and also represents the cross on which Jesus was crucified.
