Birth of Christ

The nativity of Jesus or birth of Jesus is described in the gospels of Luke and Matthew. The two accounts agree that Jesus was born in Bethlehem in the time of Herod the Great to a betrothed virgin whose name was Mary.

In Christian theology the nativity marks the incarnation of Jesus as the second Adam, in fulfillment of the divine will of God, undoing the damage caused by the fall of the first man, Adam. The artistic depiction of the nativity has been an important subject for Christian artists since the 4th century. Since the 13th century, the nativity scene has emphasized the humility of Jesus and promoted a more tender image of him, as a major turning point from the early "Lord and Master" image, which has had an effect on the basic approaches of Christian pastoral ministry.

The nativity plays a major role in the Christian liturgical year. Christian congregations of the Western tradition (including the Catholic Church, the Western Rite Orthodox, the Anglican Communion, and many Protestants) begin observing the season of Advent four Sundays before Christmas, the traditional feast-day of his birth, which falls on December 25.

Christians of the Eastern Orthodox Church and Oriental Orthodox Church observe a similar season, sometimes called Advent but also called the "Nativity Fast." This begins forty days before Christmas. Some Orthodox (e.g. The Greeks and Syrians) celebrate Christmas on December 25. Other Orthodox (e.g. The Ethiopians, Georgians, and Russians) celebrate Christmas on January 7 as a result of their churches continuing to follow the Julian calendar, rather than the modern day Gregorian calendar.

...
Wikipedia