After the liturgical reforms of Vatican II, Pope Paul VI presented a 1974 document as a "minimum repertoire of Gregorian chant" which the faithful should learn to sing. In promulgating the booklet, the Congregation for Divine Worship stated that the book would be "extremely useful if the faithful learn the chants contained in the volume, as the Pope and the Congregation for Divine Worship intend." 
The renowned Maltese choir Jubilate Deo is named after this document.
Chants of the Ordinary
|Order of Mass|
of the faithful