Musical Modes

Modes refer to a different scale pattern in terms of the position of tone and semitone intervals that may be produced by traversing the scale from different starting points. The ancient Greeks distinguished harmoniai which were scale patterns in the greater perfect system from tonoi which were the modes used in tuning and performance of a stringed instrument. Tonos meant to stretch or tension. The oldest modes Dorian, Phrygian, and Lydian are the names that Aristotle and Plato ascribe to the harmoniai. The names of the Ancient Greek modes were Dorian, Phrygian, Lydian, Mixolydian, Hypodorian, Hypophrygian, and Hypolydian. Medieval theorists tried to replicate the very ancient system of Greek modes, dividing them into pairs of modes, the Dorian and Hypodorain, etc., which were distinguished by different melodic patterns. Over a period of centuries, they were replaced by Major and Minor modes as a matter of stylistic evolution.

The modern modes are still the same as they were when they originated in Greece, but with slightly different names. Because the diatonic scale has two semitone steps and five tone steps, different patterns of intervals arise by traversing it from different starting points. These different starting points are referred to as modes of the scale. The seven modes in terms of the diatonic C major scale are: C Ionian, D Dorian, E Phrygian, F Lydian, G Mixolydian, A Aeolian, and B Locrian. The Ionian and Aeolian modes, respectively, were ancestors of the modern major scale and natural minor scale.

Gregorian chant is the plainchant of the Roman Catholic Church. It is one of the five principal repertoires of Latin liturgical chant of the Middle Ages. Plainchant is a form of musical prayer, heightened speech that unites the faithful through melody and rhythm in the articulation of devout thoughts. The Book of Psalms is the principal source of text for the Gregorian chant. The phraseology, punctuation, and syntax give form to its songful delivery. Chant is usually monophonic, consisting of a single line or melody without an accompaniment. There is a relation of notes to syllables in chants. Those chants in which almost each syllable has a single note are called syllabic. Those characterized by long melodic passages on a single syllable are called melismatic.

However, some chants that are prevailingly melismatic usually include some syllabic sections or phrases. Chants can be described as being meditative. Chants utilize the seven modes. However, most chants seem to predominantly favor the Dorian mode.