Hypophrygian mode

The Hypophrygian mode, literally meaning "below Phrygian", is a musical mode or diatonic scale in medieval chant theory, the fourth mode of church music. This mode is the plagal counterpart of the authentic third mode, which was called Phrygian. In the Middle Ages and Renaissance this mode was described in two ways: the diatonic scale from B to B an octave above, divided at the mode final E (B–C–D–E + E–F–G–A–B); and as a mode with final E and ambitus from the A below to the C above. The note A above the final (the tenor of the corresponding fourth psalm tone) had an important melodic function (Powers 2001b, 38). The melodic range of the ecclesiastical Hypophrygian mode therefore goes from the perfect fourth or fifth below the tonic to the perfect fifth or minor sixth above.