The modes · Other scales · Music theory
If you play the white keys starting on each one of them, you get seven different scales, because the half steps fall elsewhere. These are the modes, which…
The modes
If you play the white keys starting on each one of them, you get seven different scales, because the half steps fall elsewhere. These are the modes, which organized medieval and Renaissance music, with Greek names adopted in the Middle Ages. Two of them are still our scales: Ionian is the major and Aeolian, the natural minor.
They are grouped by their 3rd. With a major 3rd are Ionian, Lydian and Mixolydian; with a minor 3rd, Dorian, Phrygian, Aeolian and Locrian. Each is recognized by the note that sets it apart from the closest major or minor scale.
From the Greeks to the Middle Ages
The names are Greek, but the modes are not. The Greeks called other things Dorian or Lydian; medieval theorists reused those names for the eight church modes of Gregorian chant. Heinrich Glarean added the Aeolian and Ionian modes in 1547, which would become our minor and major.
Each mode had a final note, the finalis, where the melody ended, and a reciting tone, or tenor. There were authentic modes, extending above their final, and plagal ones, extending below it. The modes are still alive: Dorian and Mixolydian in Irish traditional music, Phrygian in flamenco, and all of them in Debussy or Bartók.