Gregorian mode

The introit Quasi modo geniti, from which Quasimodo Sunday gets its name, is in Mode 6.

A Gregorian mode (or church mode) is one of the eight systems of pitch organization used to describe Gregorian chant.

The name of Pope Gregory I was attached to the variety of chant that was to become the dominant variety in medieval western and central Europe (the diocese of Milan was the sole significant exception) by the Frankish cantors reworking Roman ecclesiastical song during the Carolingian period (McKinnon 2001). The theoretical framework of modes arose later to describe the tonal structure of this chant repertory, and is not necessarily applicable to the other European chant dialects (Old Roman, Mozarabic, Ambrosian, etc.).

Tonality

Two characteristic notes or pitches in a modal melody are the final and cofinal (tenor, dominant, or reciting tone). These are the primary degrees (often l, 5) on which the melody is conceived and on which it most often comes to rest, in graduated stages of finality (Berry 1987,^{[page needed]}). The final is the pitch in which the chant usually ends; it may be approximately regarded as analogous (but not identical) to the tonic in the Western classical tradition. Likewise the cofinal is an additional resting point in the chant; it may be regarded as having some analogy to the more recent dominant, but its interval from the tonic may not be a fifth. In addition to the final and cofinal, every mode is distinguished by scale degrees called the mediant and the participant. The mediant is named from its position between the final and cofinal. In the authentic modes it is the third degree of the scale, unless that note should happen to be B, in which case C substitutes for it. In the plagal modes, its position is somewhat irregular. The participant is an auxiliary note, generally adjacent to the mediant in authentic modes and, in the plagal forms, coincident with the cofinal of the corresponding authentic mode (some modes have a second participant) (Rockstro 1880, 342).

The eight modes are grouped into four pairs, each pair comprising an authentic mode and a plagal mode.

The eight Gregorian modes: f indicates 'final'

An authentic mode has its final as the lowest note of the scale (it may occasionally go one note below). These four modes correspond to the modern modal scales starting on D (Dorian), E (Phrygian), F (Ionian = the Gregorian Lydian), and G (Mixolydian).

A plagal mode (from Greek πλάγιος 'oblique, sideways, athwart') (Merriam Webster's 1963; Liddell and Scott 1996) has a range that includes the octave from the fourth below the final to the fifth above. The plagal modes are the even-numbered modes, 2, 4, 6 and 8, and each takes its name from the corresponding odd-numbered authentic mode with the addition of the prefix "hypo-": Hypodorian, Hypophrygian, Hypolydian, and Hypomixolydian (Powers 2001).

Given the confusion between ancient, medieval, and modern terminology, "today it is more consistent and practical to use the traditional designation of the modes with numbers one to eight" (Knighton and Fallows 1998, 256).

See also

• Musical mode
• Octoechos

References

• Berry, Wallace. 1987. Structural Functions in Music. New York: Dover Publications. ISBN 0486253848.
• Knighton, Tess, and David Fallows. 1998. Companion to Medieval and Renaissance Music. Berkeley and Los Angeles: University of California Press. ISBN 0520210816.
• McKinnon, James W. 2001. "Gregorian Chant". The New Grove Dictionary of Music and Musicians, second edition, edited by Stanley Sadie and John Tyrrell. London: Macmillan Publishers.
• Merriam Webster's Seventh New Collegiate Dictionary: A Merriam-Webster: Based on Webster's Third New International Dictionary. 1963. Springfield, Mass.: G. & C. Merriam Co.
• Liddell, Henry George, and Robert Scott. 1996. A Greek-English Lexicon, revised and augmented throughout by Sir Henry Stuart Jones and Roderick McKenzie. Oxford: Clarendon Press; New York: Oxford University Press. ISBN 0198642261
• Powers, Harold S. 2001. "Plagal mode". The New Grove Dictionary of Music and Musicians, second edition, edited by Stanley Sadie and John Tyrrell. London: Macmillan Publishers.
• Rockstro, W[illiam] S[myth] (1880). "Modes, the Ecclesiastical". A Dictionary of Music and Musicians (A.D. 1450–1880), by Eminent Writers, English and Foreign, vol. 2, edited by George Grove, D. C. L., 340–43. London: Macmillan and Co.