Gregorian chant  The Roman form of early plain chant, as
distinguished from the kindred Ambrosian, Gallican, and
Mozarabic chants, which it gradually supplanted from the 8th to
the 11th centuries. Its name derives from Pope Gregory the Great
(590-604) to whom tradition ascribes the final arrangement of
the Roman chant. Pius X, by his "Motu Proprio" of 22 November
1903, ordered the universal restoration of the authentic
Gregorian is the sole chant of the Roman Church, describing it
as the supreme type of sacred, music (which is one and the same
as liturgical music) because it contains in the highest degree
the qualities characteristic of sacred music: true art, and
holiness. It follows that Gregorian is altogether indispensable
in the celebration of the solemn liturgy, since an integral part
of that liturgy; so much so, in fact, that these liturgical
functions cannot take place if the chant be lacking. Such is the
relation between the liturgy of the Church and the music it
employs, as laid down by the papal co