Also known as the Salve Regina, the Hail Holy Queen was traditionally sun after the Compline and in some cases after Lauds or other hours. Monks would often chant it on their way back to their sleeping quarters. In the 12th century, it was written down in it's current form at the Abbey of Cluny as a processional hymn on Marian feasts. Sailors especially held the anthem dear as Father Juniper B. Carol, OFM writes in his Mariology, Volume 3:
There is considerable evidence that the hymn was popular as a song of exultant joy, a tribute more to its lilting melody [the original plainchant is indicated here] than to its references to mourning, weeping and exile. Seafaring men doubtless came to favor it because it was so eminently singable. It came to be used as part of the ritual for the blessing of a ship, and the core of evening service on shipboard. The mention of it in Columbus' journal is well-known.
Today it is well known by those who pray the Liturgy of the Hours and is often sang at the end of the day. Alphonsus di Liguori's Glories of Mary writes:
Blessed Amadeus says, 'that our Queen is constantly before the Divine Majesty, interceding for us with her most powerful prayers.' And as in heaven 'she well knows our miseries and wants, she cannot do otherwise than have compassion on us; and thus, with the affection of a mother, moved to tenderness towards us, pitying and gentle, she is always endeavoring to help and save us'.
Salve, Regina, Mater misericordiæ,
vita, dulcedo, et spes nostra, salve.
Ad te clamamus exsules filii Hevæ,
Ad te suspiramus, gementes et flentes
in hac lacrimarum valle.
Eia, ergo, advocata nostra, illos tuos
misericordes oculos ad nos converte;
Et Jesum, benedictum fructum ventris tui,
nobis post hoc exsilium ostende.
O clemens, O pia, O dulcis Virgo Maria.
℣ Ora pro nobis, sancta Dei Genitrix,
℟ Ut digni efficiamur promissionibus Christi.
O, holy Queen, Mother of Mercy,
Hail our life, our sweetness and our hope.
To thee do we cry,
Poor banished children of Eve;
To thee do we send up our sighs,
Mourning and weeping in this valley of tears.
Turn then, most gracious advocate,
Thine eyes of mercy toward us;
And after this our exile,
Show unto us the blessed fruit of thy womb, Jesus.
O clement, O loving,O sweet Virgin Mary.
℣ Pray for us, O holy Mother of God,
℟ that we may be made worthy of the promises of Christ.