In the Catholic liturgical calendar, three Masses are traditionally said that day; the custom was begun in Jerusalem.
(1) Midnight: Mass in Bethlehem to celebrate Christ's birth into the world
(2) Dawn: Mass at the Church of the Resurrection in Jerusalem to commemorate the adoration of the shepherds
(3) Midday: to celebrate the eternal generation of the Word and the dignity of the Son of God
We maintain this custom at my little chapel of St. Michael's. Below are some photos from Christmas Day, 2007.
Nave for the Laity, Sanctuary beyond the Altar Rail for the Clergy
The Main Altar Decorated for the Christmas Feast
The Reading of the GospelThe season of Christmas, or Christmas-tide, begins December 25 and runs 12 days until January 6 and the Feast of the Epiphany, which commemorates a triple manifestation of Christ:
(1) to the Magi (and by extension to the Gentile world),
(2) in His Baptism, when the Voice from heaven declared "This is My Beloved Son,"
(3) in the miracle of the changing of water into wine at the wedding feast of Cana.
Gloria in excelsis Deo.