Rhythmic Mode - History

History

Though the use of the rhythmic modes is the most characteristic feature of the music of the late Notre Dame school, especially the compositions of Pérotin, they are also predominant in much of the rest of the music of the ars antiqua through about the middle of the 13th century. Composition types which were permeated by the modal rhythm include Notre Dame organum (most famously, the organum triplum and organum quadruplum of Pérotin), conductus, and discant clausulae. Later in the century, the motets by Petrus de Cruce and the many anonymous composers, which were descended from discant clausulae, also used modal rhythm, often with much greater complexity than was found earlier in the century: for example each voice sometimes sang in a different mode, as well as a different language.

In most sources there were six rhythmic modes, as first explained in the anonymous treatise of about 1260, De mensurabili musica (formerly attributed to Johannes de Garlandia, who is now believed merely to have edited it in the late 13th century for Jerome of Moravia, who incorporated it into his own compilation) (Baltzer 2001). Each mode consisted of a short pattern of long and short note values ("longa" and "brevis") corresponding to a metrical foot, as follows (Reese 1940, 207–209):

1. Long-short (trochee)
2. Short-long (iamb)
3. Long-short-short (dactyl)
4. Short-short-long (anapaest)
5. Long-long (spondee)
6. Short-short-short (tribrach or choree)

Although this system of six modes was recognized by medieval theorists, in practice only the first three and fifth patterns were commonly used, with the first mode being by far the most frequent (Apel 1961, 223). The fourth mode is rarely encountered, an exception being the second clausula of Lux magna in MS Wolfenbüttel 677, fol. 44 (Hughes 1956a, 320). The fifth mode normally occurs in groups of three and is used only in the lowest voice (or tenor), whereas the sixth mode is most often found in an upper part (Hughes 1954a, 320).

Modern transcriptions of the six modes usually are as follows:

1. Quarter (crotchet), eighth (quaver) (generally barred, therefore, in 3/8 or, because the patterns usually repeat an even number of times, in 6/8 (Apel 1961, 221))
   Play X4
2. Eighth, quarter (barred in 3/8 or 6/8)
   Play X4
3. Dotted quarter, eighth, quarter (barred in 6/8)
   Play X2
4. Eighth, quarter, dotted quarter (barred in 6/8)
   Play X2
5. Dotted quarters (barred in either 3/8 or 6/8)
   Play X2
6. Eighths (barred in 3/8 or 6/8)
   Play X4

• Cooper (1973, 30) gives the above but doubled in length, thus 1) is barred in 3/4, for example.
• Riemann (1962, 135) is another modern exception, who also gives the values twice as long, in 3/4 time, but in addition holds that the third and fourth modes were really intended to represent the modern, with duple rhythms ( and, respectively).