a piece i'm surprised i never heard before

This is a beautiful choral version of the Angelus by Biebl. The words, in Latin (the language of the piece) and the English translation:

Angelus Domini nuntiavit Mari
et concepit de Spiritu sancto.

Ave Maria, gratia plena, Dominus tecum;
benedicta tu in muleribus,
et benedictus fructus ventris tui Jesus.

Maria dixit: Ecce ancilla Domini;
fiat mihi secundum verbum tuum.

Et verbum caro factum est et habitavit in nobis.

Sancta Maria, mater Dei ora pro nobis peccatoribus,
Sancta Maria, ora pro nobis,
nunc et in hora mortis nostr, Amen.

The angel of the Lord made his annunciation to Mary
and she conceived by the Holy Spirit.

Hail, Mary, full of grace, the Lord is with thee.
Blessed art thou among women,
and blessed is the fruit of thy womb, Jesus.

Mary said: Behold the handmaiden of the Lord.
Let it be unto me according to Thy word.

And the Word was made flesh and dwelt among us.

Holy Mary, mother of God, pray for us sinners.
Holy Mary, pray for us,
now and at the hour of our death, Amen.