Fra Angelico, c. 1430
At this day's Mass, we are to genuflect during the Creed, at the words "he was born of the Virgin Mary, and became man." Bending our knee, we pay homage to the Son, who condescended to become one of us for our salvation.
Xporta manes, et stella maris, sucurre cadenti,
surgere qui curat populo: tu quae genuisti,
natura mirante, tuum sanctum Genitorem,
Virgo prius ac posterius, Gabrielis ab ore
sumens illud Ave, peccatorum miserere.
You can hear a sample of the ancient Gregorian Chant of this antiphon here ( ".au" file). Or you can listen to a sample of John Dunstable's (c. 1370-1453) polyphonic setting here (RealAudio file).