Chromatic Alteration and Extrahexachordal Intervals in Fourteenth-century Polyphonic Repertoires

When forward thrust in counterpoint prefers causa pulchritudinis to causa necessitatis, augmented and diminished intervals result. These are important components of composers' musical vocabulary in the 14th century, although speculative theory would appear to discourage their. Fairly strict rules make it possible to identify pitch inflections when sources are unspecific or erroneous. Causa necessitatis corrects unisons, octaves, and diminished fifths, not tritones. Problems in reading inflections remain where ornamental melodic figuration obscures essential contrapuntal movement, and increase with developments in vocal texture in the 15th century. [RILM-abbrev]