Listen to O Magnum Mysterium online. O Magnum Mysterium is an English language song and is sung by The Choir of Lincoln College Oxford, Tom Lydon and Philip Smith. O Magnum Mysterium, from the album O Magnum Mysterium - Christmas Music & Carols, was released in the year 2001. The duration of the song is 3:30. Download English songs online from JioSaavn.