MUSICA FICTA

also called Musica Falsa, in medieval and Renaissance music, insertion, for theoretical or aesthetic reasons, of unnotated chromatic notes (notes not belonging to the mode of a piece) into music during performancethat is, the addition by performers of unwritten sharps and flats. This practice was responsible for the introduction of accidentals (sharps, flats, naturals) into musical notation. It also influenced the evolution of the major and minor keys on which most Western music came to be based, for it modified the medieval church modes to resemble the major and minor scales. Musica ficta occurs both in the purely melodic music of plainchant and in polyphony, or many-voiced music. While the rules of its usage are known, medieval and Renaissance music theorists disagreed about details; their views lagged behind changes in performance practice, and modern scholars differ in their opinions as to how extensively the practice was carried out. Musical manuscripts offer some clues, but accidentals were frequently omitted, for they were often considered an insult to the performer. Consequently, two modern editions of the same Renaissance piece may show slight differences in their notation of the musica ficta for the modern performer. In modern editions the editorial insertions of musica ficta are indicated by small accidental signs placed above the notes affected. Certain rules of musica ficta are believed to have been commonly applied. Generally, the tritone, for example, fb, was avoided both in melodies and between the voices of polyphonic music, with, in this case, F or B substituted as appropriate. The leading tone was often used: the seventh tone of the mode was raised a half step (for example, F might become F) when it led, or ascended, to the final note of the mode (in this case, G). For purely aesthetic reasons, an upper neighbour note might be altered (for example, aba might become aba). Other rules were applied in other instances. For example, the final chord of a piece was altered if it would not otherwise be a major triad (e.g., the chord, or triad, ceg became ceg), considered a more appropriate conclusion to a composition.