A cappella Publisher Desc.  One of a trilogy of choral settings of chant melodies from the Liber Usualis with texts by St. Thomas Aquinas (the other two being Adoro Te and Tantum Ergo). SATB (some divisi), violin (or other C instrument), medium difficulty. At one point, S1 voices state the melody alternately with the violin as other voices have descending diminished 7th chords. This gives way to each S1 voice entering randomly, and singing the melody ad lib while the violin introduces the melody of O God, Our Help In Ages Past. Approximate performance length: 3:00.