Background and history
Marian antiphons have been sung, since the thirteenth century, at the close of Compline, the last Office of the day. Peter Canisius (d. 1597) noted that one praises God in Mary when one turns to her in song. Liturgically, the Salve Regina is the best known of four prescribed Marian Anthems recited after Compline, and, in some uses, after Lauds or other Hours. Its use after Compline is likely traceable to the monastic practice of intoning it in chapel and chanting it on the way to sleeping quarters.
It was set down in its current form at the Abbey of Cluny in the 12th century, where it was used as a processional hymn on Marian feasts. The Cistercians chanted the Salve Regina daily from 1218. It was popular at medieval universities as evening song, and according to Fr. Juniper Carol, it came to be part of the ritual for the blessing of a ship. While the anthem figured largely in liturgical and in general popular Catholic devotion, it was especially dear to sailors.
In the 18th century, the Salve Regina served as the outline for the classic Roman Catholic Mariology book The Glories of Mary by Alphonsus Liguori. In the first part of the book Alphonsus, a Doctor of the Church, discusses the Salve Regina and explains how God gave Mary to mankind as the "Gate of Heaven".
It was added to the series of prayers said at the end of Low Mass by Pope Leo XIII.
The Salve Regina is traditionally sung at the end of a priest's funeral Mass by the decedent's fellow priests in attendance.
As a prayer, it is commonly said at the end of the rosary.