The Ave Regina caelorum is sung as the concluding votive antiphon of the Divine Office during the pre-Lent and Lenten seasons, i.e. from the Feast of the Presentation (2nd February) until Maundy Thursday.
It appears to be of monastic origin but the author is unknown (dating from around the 12th century). Herman Contractus (+1054) is often suggested as the author, for he wrote several popular Marian antiphons around then. This antiphon is one of the traditional concluding antiphons for Compline in use since the 13th century. It is traditionally recited from the Feast of the Purification (Feb. 2) until Wednesday in Holy Week.
The text of this antiphon appears to have remained fairly unchanged since the 12th century, small variants being noted below. Dufay's setting is unique in ending with an Alleluia, which probably stems from the earlier use of the antiphon at the Annunciation.
Ave Regina coelorum,
Ave Domina Angelorum:
Salve radix, salve porta, [or Salve, radix sancta,]
Ex qua mundo lux est orta:
Gaude Virgo gloriosa,
Super omnes speciosa,
Vale, o valde decora,
Et pro nobis Christum [semper] exora.
Dignare me laudare te Virgo sacrata
Da mihi virtutem contra hostes tuos.
Alternative Latin text
Ave regina caelorum,
ave domina angelorum,
vale stirps sancta,
per quam mundi lux est orta.
super omnes speciosa,
salve vale decora
et pro nobis semper Christum exora.
Hail, O Queen of Heav'n enthron'd,
Hail, by angels Mistress own'd
Root of Jesse, Gate of morn,
Whence the world's true light was born.
Glorious Virgin, joy to thee,
Loveliest whom in Heaven they see,
Fairest thou where all are fair!
Plead with Christ our sins to spare.
V. Allow me to praise thee, holy Virgin.
R. Give me strength against thy enemies.