The Feast of the Annunciation, in Greek, Ο Ευαγγελισμός της Θεοτόκου, contemporarily the Solemnity of the Annunciation, and also called Lady Day, the Feast of the Incarnation (Festum Incarnationis), or Conceptio Christi (Christ’s Conception), commemorates the visit of the archangel Gabriel to the Virgin Mary, during which he informed her that she would be the mother of Jesus Christ, the Son of God. It is celebrated on 25 March each year. In the Roman Catholic Church, when 25 March falls during the Paschal Triduum, it is transferred forward to the first suitable day during Eastertide. In Eastern Orthodoxy and Eastern Catholicism, it is never transferred, even if it falls on Pascha (Easter). The concurrence of these two feasts is called Kyriopascha.
The Feast of the Annunciation is observed almost universally throughout Christianity, especially within Orthodoxy, Anglicanism, Catholicism, and Lutheranism. It is a major Marian feast, classified as a solemnity in the Catholic Church, a Festival in the Lutheran Churches, and a Principal Feast in the Anglican Communion. In Orthodox Christianity, because it announces the incarnation of Christ, it is counted as one of the eight great feasts of the Lord. Examples of the importance attached to the Annunciation, especially in the Roman Catholicism, are the Angelus prayer, the event’s position as the first Joyful Mystery of the Dominican Rosary, and the Novena for the Feast of the Annunciation. – WikipediaVisit Event Site