Thus Pythagoras brought order into the music as well as into the lives of people.  But whereas it ennobled the people, it killed the music, the one vent in life through which unbounded utterance is possible; its essence is so interwoven with spirituality that to tear it away and fetter it with human mathematics is to lower it to the level of mere utilitarianism.  And so it was with Greek music, which was held subordinate to metre, to poetry, to acting, and finally became a term of contempt.  Pythagoras wished to banish the flute, as Plato also did later, and the name of flute player was used as a reproach.  I fancy this was because the flute, on account of its construction, could ignore the mathematical divisions prescribed for the stringed instruments, and therefore could indulge in purely emotional music.  Besides, the flute was the chosen instrument of the orgiastic Bacchic cult, and its associations were those of unbridled license.  To be sure, the voice was held by no mathematical restrictions as to pitch; but its music was held in check by the words, and its metre by dancing feet.

Having measured the musical intervals, there still remained the task of classifying the different manners of singing which existed in Greece, and using all their different notes to form a general system.  For just as in different parts of Greece there existed different dances, the steps of which were known as Lydian, Ionian, Locrian, and Dorian feet, and so on, so the melodies to which they were danced were known as being in the Lydian, Ionian, Locrian, or Dorian scale or mode.  In speaking of Hindu music, I explained that what we call a mode consists of a scale, and that one mode differs from another only in the position of the semitones in this scale.  Now in ancient Greece there were in use over fifteen different modes, each one common to the part of the country in which it originated.  At the time of Pythagoras there were seven in general use:  the Dorian, Lydian, Aeolian or Locrian, Hypo- (or low) Lydian, Phrygian, Hypo- (or low) Phrygian, and Mixolydian or mixed Lydian.  The invention of the latter is attributed to Sappho by Plutarch, quoting Aristoxenus.

These modes were all invested with individual characters by the Greeks, just as in the present day we say our major mode is happy, the minor sad.  The Dorian mode was considered the greatest, and, according to Plato, the only one worthy of men.  It was supposed to have a dignified, martial character.  The Lydian, on the other hand, was all softness, and love songs were written in it.  The Phrygian was of a violent, ecstatic nature, and was considered as being especially appropriate for dithyrambs, the metre for the wild bacchanalian dances.  For instance, Aristotle tells how Philoxenus attempted to set dithyrambic verse to the Dorian mode, and, failing, had to return to the Phrygian.  The Mixolydian, which was Sappho’s mode, was the mode for sentiment and passion.  The Dorian, Phrygian, and Lydian were the oldest modes.