The text of this well-known Gregorian chant was written by St. Thomas Aquinas (1225-1274), to commemorate the Feast of Corpus Christi in 1264. The composer of the music itself is unknown, as is the case with virtually all of the Gregorian chant repertoire. Rhett Barnwell’s intermediate harp arrangement is in the key of D (2 sharps), with no lever or pedal changes required. There are 2 pages of music, and both Latin and English texts are provided. It is a perfect piece for communion in a church service or any occasion for quiet meditation.