Cantus planus [planus cantus; musica plana] (Lat.: ‘plainchant’)
- Jeffrey Dean
[planus cantus; musica plana] (Lat.: ‘plainchant’)
A term used to describe plainchant. In its earliest usage by Odo and Guido of Arezzo it signified chants at a lower pitch (‘cantus … graves et plani’) as distinct from those at a higher pitch (‘cantus … acuti et alti’), in order to distinguish the plagal modes from the authentic; in this sense planus and acutus are exactly equivalent to their literal translations ‘flat’ and ‘sharp’. Apart from these two appearances the term was scarcely used before the 13th century, when it began to designate plainchant as distinct from, first, discant and, slightly later and more importantly, mensural music. ‘Cantus planus’ was almost never used in the sense of Cantus firmus to mean the tenor of a polyphonic composition, except in the case of organum purum, where the chant melody retained its non-mensural character. Anonymus 4 (CoussemakerS, i) made an interesting opposition between ‘cantores plani’, who sang parallel organum, and ‘veri discantatores’, who discanted in contrary motion....