Note 23 — Chapter VII · The Cavalier of Music
George P. (George Putnam) Upton translation
The Antiphonarium Romanum is a collection of the plain song melodies handed down in the Roman church by tradition, and compiled by Saint Gregory with many of his compositions added. For many centuries after his death it was regarded as the authority in church music. The chants adapted to the Psalms are the more important parts of plain song.