The Ave Regina Caelorum is the Marian antiphon sung during Lent. Its origins and composer are unknown, but manuscripts exist from the early 12 century onwards. There is the standard Gregorian chant, sung at Compline each night:
But there are also any number of polyphonic renditions.
Alonso Lobo (1555 – 1617) was a Spanish composer, a near-contemporary of the great Palestrina and Victoria, famous during his lifetime, and considered their equal, or near thereto, even if he has drifted somewhat more into obscurity. But his music – all of it polyphonic and choral, with no instrumental pieces surviving – is ineffably beautiful and masterfully harmonized.
Compare and complement with the same motet by the incomparable Palestrina (1525 – 1594):
And a final version by Tomás Luis de Victoria (1548 – 1611), whose life almost perfectly spans Lobo’s: