
Per Musi | Belo Horizonte | v.26 | General Section | e252616 | 2025
Crowley, Emmet; Martin, Francisco Gómez. “Non-octave-repeating scales as a form of tonal organization”
The scale is most likely of Byzantine origin and the notes within it are classified according to their position
within the tetrachord and named by Greek ordinal numbers, which also denote the four basic modal
categories in Byzantine tradition: I=protus, II=deuterus, III=tritus, IV=tetrardus (Cohen 2008). Since the
intervallic structure is repeated at the fifth, each of the four notes within the tetrachord can act as the tonic
of a distinct “fifth-repeating” mode. Thus, the names of the individual pitches refer to both the pitch itself
and the modal quality it embodies, given its place within the tetrachord. As Cohen explains,
The first note of each and every tetrachord has the same modal quality (protus), and thus
the same name (protus), and so too for the other three notes. That is, since there are only
four different tetrachordal positions, each of which creates (by its pattern) one of the four
basic modal qualities by which the notes are identified, there are, in a sense, really only
four truly different’ notes, all the others being replications of these at higher and lower
levels of pitch, separated by perfect fifths. (In a similar way, the octave periodicity of our
modern system makes it possible to operate with pitch classes.)(Cohen 2008, 325–326)
The concept of modal quality is integral to pitch conception in the Enchiriadis scale and the scale has a clear
pedagogical and theoretical purpose, namely, to explain and help the student distinguish the four “modal
qualities” associated with each note—protus, deuterus, tritus and tetrardus (Cohen 2008, 325–326). Each
tetrachord is repeated at the interval of a perfect fifth, creating a periodicity analogous to that found in
octave-repeating scales. In fact, as can be observed in many of the examples throughout the text, most non-
octave-repeating scales tend to repeat at an interval smaller or even greater than the octave. In the case of
the Enchiriadis scale, the notes which constitute the repeating tetrachord are indeed treated as equivalent
throughout the scale, creating a periodicity and general pitch space much like that of octave-repeating-
scales, such as the diatonic scale in Western Music. Although it is clear that the Enchiriadis scale fulfilled the
pedagogical and theoretical purpose of explaining the modal qualities of melodies (Cohen 2008, 326), it has
also been suggested that it represents the actual tone system used in plainsong (Maloy 2009, 75).
2.2. The Znamenny scale and other fourth- and fifth-equivalent pitch sets
Scales based on a succession of similar trichords/tetrachords were employed in Medieval Western Europe—
and in countries such as Russia, Bulgaria, Georgia, Azerbaijan or Armenia—as a melodic framework in
Christian plainchant, ultimately influencing the traditional music of various Eastern Orthodox regions and
cultures (Nikolsky 2016, 8–9). These scales are constructed by stringing together similar
trichords/tetrachords, generally at the interval of a fourth or fifth, throughout various octaves. Hence, pitch
content differs in consecutive octaves. The resulting scale is treated as a single entity and is especially
pronounced in a polyphonic setting (Nikolsky 2016, 8). An example of such a scale is that of the Znamenny
rospev, the chant of the Russian Orthodox church. Most likely a transformation of Byzantine chant which
entered Russia in the tenth century at the time of Christanization (Swan 1940b, 232), its name, literally
“chanting by signs”, is a reference to the neume system originally used to notate the music (Velimirovic et
al. 2001). The system—initially very similar to Early Byzantine Notation (Swan 1940b, 232), indicating only
intervallic relations rather than discrete pitches (Velimirovic et al. 2001)—gradually evolved into a form of
pitch-specific notation. The gamut encompassing the notes of the melodies used in the chants most likely
emerged in the first major notational reform of the seventeenth century, associated with the theorist Ivan
Shaydur (Velimirovic et al. 2001). It consists of four consecutive major trichords at the distance of a semitone,
forming a scale with an intervallic span of a perfect twelfth.