Today's Points from Apel's Gregorian Chant, Chapter One, Definition and Terminology
Polyphonic (multivoiced) music developed from chant. (This development was illustrated very well for me the first time I saw Professor Mahrt teach, at a Saturday singer's workshop. He began by teaching us to sing a chant whose single melodic line was incorporated into a later polyphonic piece that we then sang together in parts. So during that hour, we sung through the evolution of polyphonic music from chant.)
+ After chant's first one thousand years of vital growth, polyphonic music started to challenge its parent.
+ Beginning in the fifteenth century, organ music too "became a successful competitor."
+ Ideas "arising in the sixteenth century ... led to a revision of the old melodies, a revision actually amounting to a complete distortion of their essential qualities."
+ In the seventeenth and eighteenth centuries, chant "was only a shadow of its former self, and . . . threatened with extinction."
+ A group of scholars, mostly French, rescued chant by studying the medievel manuscripts and "brought the old tradition to new life." L. Lambillotte was one of the first, and the monks of Solesmes followed.
+ In 1903, chant was "officially adopted by the Roman Church" under Pope Pius X, starting the third millennium of Gregorian chant.
Chant is purely melodic, purely vocal, sung by one or several singers. It does not use harmony, counterpoint, or any other kind of accompaniment. And it does not have strict meter and measure.
Gregorian refers to Pope Gregory I (590 - 604). He played an important role in the final arrangement of the chants. Scholars disagree about the exact nature of his contribution. Sometime, either during or after Pope Gregory, the chants were assigned to specific occasions of the Church year.
To avoid some difficulties, some use the term "Roman chant" instead of Gregorian. But, Apels points out, Gregorian chant is not merely of Roman origin. Another term whose first documented use was in the tenth century and which was "universally employed in the later Middle Ages is cantus planus" plain song or plain chant.
From a footnote:
The original meaning of cantus planus (which means plane chant, with plane meaning lying flat), was used for chants in plagal modes.
Gregorian or Roman chant is one of several that devoped in Western Europe, all using Latin. Interestingly enough, the official language of the Church was originally Greek, not replaced with Latin until the third or fourth century.
Four branches or dialects of Western chant are:
+ Gregorian in Rome
+ Ambrosian (after St. Ambrose) in Milan
+ Gallican in France
+ Mozarabic (or Visigothic) in Spain
Little remains of the Gallican and Mozarabic. But both Gregorian and Ambrosian chant are in use until this present day.
In 1958, when the book was written, research revealed another dialect of Western chant, "Old-Roman" or "City-Roman."