Choir of the New College, Oxford
The director isn't named.
As one of the comments say, there are a few problems with the audio but the score is there.
William Byrd - O Magnum Mysterium
Jenny Högström, Soprano
Laura Binggeli, Alto
Dino Lüthy, Tenor
Daniel Pérez, Bass
Stefan Müller, director
Update: If you hadn't guessed, I'm posting different settings of this text from the Christmas Matins office service. I didn't know how many really fine ones there were until I started looking for them. While there aren't as many as for the Magnificat, there are more than will fit into the next five days. I may continue it past Christmas day.
O great mystery,
and wonderous sacrament,
that animals should see God born,
lying in a manger!
It was brought to mind by the passage in Isaiah I noted the week before last, "Then the glory of the LORD shall be revealed, and all flesh shall see it together." I've never found the dogma that animals don't have immortal souls to be either convincing or congenial. My friend RMJ notes that Luke is a subtle theologian, I wonder if his noting that Jesus was born in a stable and laid in a manger, from which animals eat, isn't him noting that the animals were a witness to God made flesh as well as people. I would think that implies that they have a higher status than soulless objects. The text of this chant calls animals seeing God born, lying in a manger a sacrament. The old Catholic Encyclopedia, in its long article on the definition of sacraments begins, "Sacraments are outward signs of inward grace, instituted by Christ for our sanctification." Yet, in this chant, the outward sign is made to animals as well as people. And, in Luke, it is the humblest of people who live in closest proximity to animals who are the first to whom it is announced, it's in Matthew that the wise and mighty find signs of it in their astrology.
That's one of the things that make this about my favorite Christmas text, as I mentioned in a previous year, the setting by Tomas Luis Victoria about my favorite of all. I'll post that sometime during the week.