The ecclesiastical modes are equivalent to the modes of our present-day key of C major. Originally, only the modes beginning on the notes D, E, F and G were used, with the modes on A and C being added in 1547. The mode on B was not used at all.
Names, taken from ancient Greek music, were given to the modes. These names are still used today for labelling the modes of a major scale. They are:
- Ionian – for the mode with a final on C (final is the old term for the note we now call the root)
- Dorian – for the mode with a final on D
- Phrygian – for the mode with a final on E
- Lydian – for the mode with a final on F
- Mixolydian – for the mode with a final on G
- Aeolian – for the mode with a final on A
and for the mode built on our modern major scale’s seventh degree,
- Locrian – for the mode with a final on B.
The main differences between the ecclesiastical modes and the modern major-scale modes is the inclusion of the Locrian mode, and the ability of the modern modes to be used with any major scale, not just C. Therefore, while the music of the Medieval and Renaissance periods essentially only used the ‘white notes’ of the piano, modern major-scale modes include all major keys. It is the same scalic combination of half and whole steps (minor and major seconds) across all of the modes which allows them to be used in any key.
In the following example you can see that both the D Dorian and E flat Dorian modes have the same scalic intervals beginning from their finals: whole step (WH), half step (HS), whole step, whole step, whole step, half step, or, major 2nd (M2), minor 2nd (m2), major 2nd, major 2nd, major 2nd, minor 2nd.
A similar combination of half and whole steps would also be present in each of the other modes.
With this in mind we can begin to see, and hear, some of the characteristics of each mode. For example, if we create triads on the final of each mode we see that Ionian, Lydian, and Mixolydian have major triads, while Dorian, Phrygian, and Aeolian have minor. The Locrian has a diminished triad which is the reason why composers initially rejected its use, claiming the diminished triad was too unstable to act as a final chord. If we place this information on a C major scale
we see that we have a harmonised major scale, which again has the same succession of major, minor and diminished chords found across all major scales.
Because of the major chord on the final, the Ionian, Lydian and Mixolydian modes are sometimes referred to as major modes, while Dorian, Phrygian and Aeolian are sometimes known as minor. You may have already noticed that the Ionian and Aeolian modes are the same as the major and natural minor scales respectively. Some characteristics of the remaining modes include:
Dorian sounds like the Aeolian mode with a raised sixth degree
Phrygian has a minor second interval above its final
Lydian contains a tritone above its final
Mixolydian sounds like Ionian with a lowered seventh degree
and Locrian contains a diminished triad on its final.
It is important to get some familiarity with the sounds and characteristics of each mode and not just treat them as theoretical formulas.
Now that a connection has been established between the ecclesiastical modes and the modern major-scale modes, let us focus on how composers of the fifteenth and sixteenth centuries used them.
B flat was the only accidental added with any regularity to Renaissance contrapuntal textures (as music developed composers did, however, begin to add accidentals other than B flat). Typically, B flat’s inclusion was to correct the tritone by lowering a B natural to B flat; the tritone could either be melodic or harmonic. Without tritone corrected
with tritones corrected
Often composers would also lower an upper neighbour note B to B flat
The only other accidentals used were to raise the leading notes of certain modes at cadences. Modes, such as Ionian and Lydian, already possess a semitone under their finals so do not require the leading note to be raised.
Dorian, Mixolydian and Aeolian all require accidentals to raise the leading note and create the characteristic vertical (harmonic) minor third interval between the leading note and the note approaching the final from above
The Phrygian mode is the exception as, even though it lacks a semitone under its final, its leading note cannot be raised as the resulting harmonic interval would be a diminished third – a dissonant interval
The Phrygian mode cadences by the F note moving down a semitone to E and the D note moving up a tone to E. This forms what is known as a Phrygian cadence.
With the inclusion of a B flat, these intervals can also form a Phrygian cadence on A, which is the other note commonly used for the Phrygian cadence
At cadences, the leading note was always staggered by a suspension formed against the note falling by step to the final. In Dorian
the suspension is approached by the D half note which creates an interval of a second with the upper voice and moves to the leading note, creating the harmonic minor third. This is called a 2-3 suspension, and is a lower voice suspension. The parts may also be swapped so that the suspension is in the upper voice.
Here, the parts form a 7-6 suspension, notice the vertical minor third is now a major sixth, the inversion of a minor third.
Other suspensions are possible, and can also be used at non cadential locations. The key points to remember with suspensions are:
- cadential suspensions always suspend the leading note
- ALL suspensions contain three elements: a preparation, which is a consonance; a suspension, which is a dissonance; and a resolution, which is a consonance
- ALL suspensions in this era must occur on strong beats. In the examples above, the preparation is on beat two, the suspension is on beat three (a strong beat) and the resolution is on beat four.
The use of dissonance was very controlled in this era, aside from the suspension, and the use on weak beats of the descending accented passing notes, dissonance was generally used on offbeats. Looking at the beginning of Sicut rosa by Lassus (below),
we see that consonant harmonic intervals are used on all beats (compound intervals are written as if they are within the octave). Note: the use of many bare harmonic octave and fifth intervals (eight in the opening four bars above) helps to give this music its characteristic sound.
Melodic intervals were also controlled so that intervals such as the tritone, major and minor sevenths, and major sixths were essentially never used. Not only was it the sound of these intervals which deterred composers from their use, but they were also considered difficult to sing; remember, it is essentially vocal music which we are dealing with.
In this era, because only ‘white notes’ were used, and accidentals were added where required in the texture, Medieval and Renaissance music typically lacked key signatures. The only exception was the use of a B flat as a key signature, like the modern F major/D minor. The addition of a B flat as a key signature means that all modes can be transposed up a fourth but still retain the same scalic intervallic succession.
The transposed modes gave composers extra ‘colour’ to use in their compositions. Rather than always having the Dorian mode with its final on D and all intervals relating to this note, the transposed Dorian gave the same sound as a Dorian mode but the intervallic relationships were now with the final G.