The Hypolydian mode, literally meaning "below Lydian", is the common name for the sixth of the eight

church modes A Gregorian mode (or church mode) is one of the eight systems of pitch organization used in Gregorian chant. History The name of Pope Gregory I was attached to the variety of chant that was to become the dominant variety in medieval western and ...

of medieval music theory. The name is taken from Ptolemy of Alexandria's term for one of his seven ''tonoi'', or transposition keys. This

mode Mode ( la, modus meaning "manner, tune, measure, due measure, rhythm, melody") may refer to: Arts and entertainment * '' MO''D''E (magazine)'', a defunct U.S. women's fashion magazine * ''Mode'' magazine, a fictional fashion magazine which is ...

is the plagal counterpart of the authentic fifth mode. In medieval theory the Hypolydian mode was described either as (1) the

diatonic Diatonic and chromatic are terms in music theory that are most often used to characterize scales, and are also applied to musical instruments, intervals, chords, notes, musical styles, and kinds of harmony. They are very often used as a ...

octave species In the musical system of ancient Greece, an octave species (εἶδος τοῦ διὰ πασῶν, or σχῆμα τοῦ διὰ πασῶν) is a specific sequence of intervals within an octave. In '' Elementa harmonica'', Aristoxenus clas ...

from C to the C an octave higher, divided at the final F (C–D–E–F + F–G–A–B–C) or (2) a mode with F as final and an ambitus from the C below the final to the D above it. The third above the final, A—corresponding to the

reciting tone In chant, a reciting tone (also called a recitation tone) can refer to either a repeated musical pitch or to the entire melodic formula for which that pitch is a structural note. In Gregorian chant, the first is also called tenor, dominant or tub ...

or "tenor" of the sixth psalm tone—was regarded as having an important melodic function in this mode. The sequence of intervals was therefore divided by the final into a lower

tetrachord In music theory, a tetrachord ( el, τετράχορδoν; lat, tetrachordum) is a series of four notes separated by three intervals. In traditional music theory, a tetrachord always spanned the interval of a perfect fourth, a 4:3 frequency pr ...

of tone-tone-semitone, and an upper pentachord of tone-tone-tone-semitone. However, from as early as the time of Hucbald the Hypolydian mode—even more than the corresponding authentic mode, the Lydian—was characterized by the predominance of B instead of B as the fourth degree above the final. The melodic centering on F and A, as well as the use of B instead of B, is illustrated in the accompanying example from the Requiem Mass introit, "Requiem aeternam". Finer distinctions among the scale degree are sometimes made, with the D below the final called the "mediant", the lowest note, C, the "participant" (a tone functioning as an auxiliary to the mediant), the G, B, and B the "conceded modulations" (subsidiary degrees), and the lowest C, the final, F, and (rarely) the D the "absolute initials".

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Further reading