The tenor, or reciting note, is found in the following manner:

In authentic modes, the tenor is a fifth above the final (or tonic).

In plagal modes (which are the modes a fourth below the authentic modes), the tenor is a third below the tenor of the corresponding authentic mode.

Whenever the tenor would fall on B, it moves to C.

Some of the earlier chants are in modes more closely related to the ethnic modes. For example, a Byzantine nun named Kassia, who wrote chants in the 9th century, used B as a reciting note in the Phrygian,.

In 1547, the Swiss scholar Glarean (or Glareanus) categorized the modes into fourteen possible patterns, of which he rejected two (the Locrian and the Hypolocrian) as "defective." The names he used for the C mode (Ionian, which resembles our modern major), the A mode (Aeolian, the "natural minor") and the Locrian are all modes that had been referred to by the ancient Greeks, though Apollo only knows what they meant by them. The Glarean system is the basis for the heptatonic "ethnic mode" system given next.

Least common is the Locrian, which is occasionally found in Icelandic and Greek music.

Some scholars include the Harmonic Minor, A-A with G raised, as an eighth mode. This is common in Welsh and some Semitic music. There are also modes based on this scale pattern, e.g., Phrygian with a major 3^rd, often used in Eastern European dance music.

The first basic scale given is with the B omitted, the second with the F. The Hexatonic mode which would be ambiguous between the Locrian and Lydian is impossible due to the omission of the tonic. The Dorian/Aeolian is very common in traditional music, as is the Ionian/Mixolydian.

There are some hexatonic modes found in traditional music which follow other patterns, such as the Ionian without the sixth scale degree and the Lydian with no seventh.
There is also one common hexatonic mode based on the harmonic minor tuning pattern; it omits the sixth scale degree, and is common in African-American music.

The first basic scale given is with F & B omitted, the second with C & F, the third with B & E. There are two impossible pentatonic modes: the Lo/Ly/P, omitting the 1st and 5th; and the Ly/I/Lo, omitting the 1st and 4th. Sometimes the I/Mi/Ly is called the major pentatonic, and the A/P/D the minor pentatonic, but all five occur in traditional music. An example of a plagal, pentatonic tune is "Amazing Grace."

There are also limited-range tunes which never go beyond the first four or five notes of the scales; sometimes they include the seventh (usually as a leading tone), but not the fifth or sixth. There are also pentatonic modes that have five adjacent notes and then skip two notes but include the higher octave such as 123451 or 7123471. I've seen a number of these in French and Hebridean music; an example is the French carol "Entre le Boeuf."

It's worth noting that some modes are more in use in certain parts of the world, and that some types of sacred music are more likely to use a particular mode. Unfortunately, I lost some of my notes on this area, so I am omitting some generalizations from previous versions of this site.

According to a survey of the songs collected and printed in the English Journal of the Folk Song Society from 1899-1931, the following modal frequencies were observed:

*Other includes pentatonic, hexatonic, and those of mixed mode or scale.

Welsh music, and some Irish and English music especially of the 15th through 18th centuries, use the Harmonic minor extensively.

Acknowledgements and thanks:

My teachers and professors, especially Therese Schroeder-Sheker, Ann Heymann, Dr. Larry Worster, Dr. Bill Morse, Dr. Hal Tamblyn, Dr. Cherise Leiter and Dr. Nancy Gunn.