The Hypoaeolian mode, literally meaning "below Aeolian", is the name assigned by Henricus Glareanus in his Dodecachordon (1547) to the musical plagal mode on A, which uses the diatonic octave species from E to the E an octave above, divided by the final into a second-species fourth (semitone–tone–tone) plus a first-species fifth (tone–semitone–tone–tone): E F G A + A B C D E (Powers 2001). The tenor or reciting tone is C, mediant B, the participants are the low and high Es, the conceded modulations are G and D, and the absolute initials are E, G, A, B, and C (Rockstro 1880, 342).
For his plainchant examples Glarean proposed two important and well-known Gregorian melodies normally written with their finals on A: the antiphon Benedicta tu in mulieribus (traditionally designated as transposed Hypophrygian) and the gradual Haec dies—Justus ut palma (traditionally designated as transposed Hypodorian) (Powers 2001).
- Dickson, Douglas. 1937. "Palestrina's 'Song of Solomon'". Music & Letters 18, no. 2 (April): 150–57.
- Powers, Harold S. 2001. "Hypoaeolian". The New Grove Dictionary of Music and Musicians, second edition, 29 vols., edited by Stanley Sadie and John Tyrrell, 12:36. London: Macmillan Publishers. ISBN 978-1-56159-239-5
- 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, 340–D. C. L. London: Macmillan and Co.