Leonin

Léonin

... All that is known about him comes from the writings of a later student at the cathedral known as Anonymous IV, an Englishman who left a treatise on theory and who mentions Léonin as the composer of the Magnus Liber, the "great book" of organum ... Much of the Magnus Liber is devoted to clausulae—melismatic portions of Gregorian chant which were extracted into separate pieces where the original note values of the chant were greatly slowed down and a fast-moving upper part is superimposed ...