Also called "Tone 8," and by the ancient Greeks called the Hypomixolydian, Plagal of the Fourth Mode is a variant of one of the diatonic modes of Byzantine Chant music. It has several variants of which note is treated as the ison (tonic and concluding) pitch, but most commonly it treats the note Ni (corresponding to Re in solfege) as ison, making it functionally equivalent to a modern Dorian Mode scale. Its second most common variant features the note Ga (corresponding to Sol in solfege) as ison, which corresponds to a modern Mixolydian Mode; in this variation, the mode arrives at this tonic through a phthora, a "corruption" resulting in the modulation from one scale to another, beginning on Ni. The Eirmologic Variant of the Plagal Fourth sometimes also lowers the pitch Zo by a half tone, equivalent to Ti in solfege, and Ke is lowered by a quarter tone, placing it *between Ti and Te in solfege (which has no widely-adopted convention for depicting quarter tones). The apichema, the idiosyncratic melodic phrase most often used to transition from other modes into Plagal of the Fourth, is "Neagie."
According to the Byzantine musicologist Savas I. Savas, the character of the Plagal Fourth Mode is humble, appeasing, tranquil, restful, and distinguished by expressions of pleading and suffering. In the Paraklitike, the primary textual source of Byzantine liturgical music, Plagal of the Fourth is characterised thus:
Seal of the tones, O Plagal of the Fourth, as bearing in yourself all fairest sounds. You broaden out the ranges of the songs, the final flourish of the Tones, and end. As limit in both notes and voices’ pitch, limit of sound I call you twice, and end.
In the Eastern Orthodox Church, music using Tone 8 is performed on "Bright Saturday" at the end of Bright Week that follows the Sunday of Pascha, and the mode is also used on every eighth Sunday liturgical service, in rotation with the other seven Byzantine modes.
Some hymns which commonly or solely use the Plagal Fourth include the Stichologia, the Prokeimena, the Apolytikia, the Dismissal Theotokia, the Doxastika, the Canon of the Cross, the Troparion for the Holy Fathers, the Troparion of Pentecost (Most Blessed Art Thou, O Christ Our God), and the Cheroubika.
Pronunciation of each note in the scale is given first in Greek, then in English in parentheses, followed by its corresponding tone in solfege.
Ascending:
ΝΗ (Ni, Re) - ΠΑ (Pa, Mi) - ΒΟΥ (Vou, Fa) - ΓΑ (Ga, Sol) - ΔΗ (Di, La) - ΚΕ (Ke, Ti*) - ΖΩ (Zo, Do or Ti) - ΝΗ (Ni, Re)
Descending:
ΝΗ (Ni, Re) - ΖΩ (Zo, Do or Ti) - ΚΕ (Ke, Ti*) - ΔΗ (Di, La) - ΓΑ (Ga, Sol)- ΒΟΥ (Vou, Fa) - ΠΑ (Pa, Mi) - ΝΗ (Ni, Re)
Iron Noder 2022, 8/30