The Feast of the Annunciation or Solemnity of the Annunciation commemorates the announcement of the archangel Gabriel to Mary, that she would miraculously conceive and give birth to a son, becoming the mother of Jesus Christ, the Son of God, marking his incarnation. It is celebrated on 25 March, which is nine months before Christmas in Western Christianity and the traditional date of the spring equinox. However, if 25 March falls either in Holy Week or in Easter Week, the feast is postponed to the Monday after the Second Sunday of Easter. Other names for the feast include Annunciation Day, Lady Day, the Feast of the Incarnation, and Conceptio Christi (Christ's Conception). The Feast of the Annunciation is observed almost universally throughout Christianity, especially within the Catholic Church, the Eastern Orthodox Church, Lutheranism, and Anglicanism. It is a major Marian feast, classified as a solemnity in the Catholic Church, a Festival in Lutheranism, and a Principal Feast in the Anglican Communion. In the Eastern Orthodox Church, because it announces the incarnation of Christ, it is counted as one of the eight great feasts of the Lord. The importance attached to the Annunciation, especially in the Catholic Church, are the Angelus and the Hail Mary prayers, the event's position as the first Joyful Mystery of the Dominican Rosary, the Novena for the Feast of the Annunciation, and the numerous depictions of the Annunciation in Christian art.