One of the two tonoi (the other being Hyperlydian) added to Aristoxenus's system of 13; Alypius (c360) was the first to mention these. Glarean used the term in the Dodecachordon (1547) to designate the octave species B–b divided at f; thus B–c–d–e–f + f–g–a–b. Although he did not accept it as one of his 12 modes, he nonetheless printed examples of it. Chapter 8 of the second book gives a plainsong melody invented by Glarean himself which, in turn, became the basis for the three-part polyphonic example of Hyperaeolian commissioned from his friend Sixtus Dietrich, and which appears as ex.47 in the third book (ex.48 is the Christe from a mass by Pierre de La Rue). The Hyperaeolian octave species was thus the basis of what is now popularly referred to as the Locrian mode.
HAROLD S. POWERS