Anonymous IV's statement that Perotin shortened the Magnus Liber and made "many better clausulae or puncta" testifies to two different types of revision. In the first case, existing discantus passages were replaced by more newly-composed ones; sometimes, this serves to actually lengthen the passage in question. In the other case, existing organum passages were replaced by discantus. This hypothesis is supported by the way in which the substitute clausulae are arranged within the fascicles by the scribe of Florence, Bibl. Laurenziana, pluteus 29.1.

Works: Regnum mundi (148); Alleluya: Nativitas (152-56).

Index Classifications: Polyphony to 1300

Contributed by: Felix Cox