Christmas is an annual festival commemorating the birth of Jesus Christ, observed primarily on December 25 as a religious and cultural celebration among billions of people around the world. Christmas is celebrated to remember the birth of Jesus Christ, who Christians believe is the Son of God. The name 'Christmas' comes from the Mass of Christ (or Jesus). A Mass service (which is sometimes called Communion or Eucharist) is where Christians remember that Jesus died for us and then came back to life.The first time the birth of Jesus Christ was attributed to the date December 25 was in the 4th century, according to early Roman history. Early celebrations of Christmas are thought to have derived from Roman and other European festivals that marked the end of the harvest, and the winter solstice.