The Feast of the Annunciation, contemporarily the Solemnity of the Annunciation, 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.
It is a principal Marian feast, classified as a solemnity in the Catholic Church. Two examples in Catholicism of the importance attached to the Annunciation are the Angelus prayer, and the event's position as the first Joyful Mystery of the Rosary.
Here is recorded the "angelic salutation" of Gabriel to Mary, 'Hail, full of grace, the LORD is with thee" (Ave, gratia plena, Dominus tecum; Luke 1: 28), and Mary's response to God's will, "Let it be done to me according to thy word" (fiat mihi secundum verbum tuum; v. 38). The "angelic salutation" is the origin of the Hail Mary prayer and the Angelus; the second part of the prayer comes from the salutation of Saint Elizabeth to Mary at the Visitation.
The Feast of the Annunciation was celebrated as early as the fourth or fifth century.The first certain mentions of the feast are in a canon, of the Council of Toledo in 656, where it was described as celebrated throughout the Church, and in another of the Council of Constantinople "in Trullo" in 692, which forbade the celebration of any festivals during Lent, excepting the Lord's Day (Sunday) and the Feast of the Annunciation. A Synod of Worcester, England in 1240 forbade all servile work on the feast. As this feast celebrates the Incarnation of the Second Person of the Trinity, many Church Fathers, including St. Athanasius, St. Gregory of Nyssa, and St. Augustine, have expounded on it.