original Dorian mode changed to (a) chromatic and (b) enharmonic: Hyperphrygian Mode.
Each mode was said to have its characteris tic quality or sentiment; the Dorian seems to have been the favorite one for heroic utter ance, while the Lydian was said to be languish ing and erotic.
The modes were afterward increased to 15, at least three of which were mere trans positions by octaves of earlier modes. In fact some theorists hold that the later development of the Greek modes completely changed their original significance and that instead of their being different arrangements of whole and half tones in a scale they were all identical in for mation and were in fact merely Dorian modes of different pitch. If this is so they should not be called modes at all, but keys, as in modern music. The modern system of equal or even temperament (see TEMPERAMENT) adopted and developed by Johann Sebastian Bach early in the 18th century and in general use since the middle of the 19th century, would thus appear to have been known to some extent among the ancient Greeks. The titles of the modes seem to contradict this theory, but the subject is so confused and the different theories so difficult of proof that wide differences of opinion will probably always exist. The complete list of the 15 modes is as follows, the pitch given being said to be the accepted one for each mode (or key): Fourths below Originals Fourths above Hypodorian (A) Dorian (D) Hyperdorian or Mixolydian (G) Hypoionian (Bb) Ionian or Hyperionian (Ab) • Iastion(1) Hypophrygian (B) Phrygian ( Hyperphrygian or Locrian (A) Hypowoban (C) Hyperwolian (Bb) Hypolydian (CP Lydian (FIB Hyperlydian (BM The Greeks had in addition three kinds of chromatic modes and an enharmonic mode. They were all modifications of one or both of the interior tones of the tetrachord, the outer tones of which were never allowed to change their relative pitch. These modes had no sig nificance in the history of music and were not adopted by the Romans.
The following are examples of Pythagoras' The X is used to represent a sound one quarter of a tone higher than the one preced ing it.
The Gregorian or ecclesiastical modes are based on the Greek modes, though many errors and changes of names were made in arranging the system. Saint Ambrose, bishop of Milan, chose four of the ancient modes which he named Authentic. Gregory the Great is said to have added four others called Plagal. Six more were afterward added, making 14, two of which were declared imperfect and rejected. There are two kinds of Gregorian modes, the Authentic and the Plagal. The final or key note of the authentic modes is the lowest note of its scale. Each authentic mode has an at tending plagal mode, a fourth below it, the keynote of which is the same as that of the authentic mode. The plagal modes are there fore similar in this sense to the Greek modes, the fourth notes of which were said to be key notes. The Gregorian modes are numbered, the authentic receiving the odd and the plagal the even numbers. In addition, the old Greek names are used, the plagal modes receiving the prefix hypo, hut unfortunately the Gregorian and Greek titles do not correspond, causing great confusion in all references to the modes. Thus, the Gregorian Hypophrygian is the same as the Greek Hyperdortan and the Gregorian Hypomixolydian with the Greek Phrygian.
As in the Greek modes it is convenient to remember the Gregorian modes by imagining a series of scales, all of natural notes and an octave in compass, beginning on each of the seven notes. These are the authentic modes from which the plagal with their prefix hypo can be readily counted. (It should be remem bered that the pitch is entirely relative as in the Greek scales).
The Gregorian modes arc still in use in the Roman Catholic Church, to the services of which it adds a remarkable effect of antiquity and solemnity.
In modern music hut two of the old modes remain; the major, equivalent to the Greek Hypophrygian (or Hyperlydian) and the Gre gorian Ionian, and the minor, equivalent to the Greek Dorian and the Gregorian }Eolian.