Basic textbook descriptions of the church modes seem clear, but I find things confusing when looking at actual compositions. I especially don't understand what "plagal" modes really means.
I have a book, Helmore, Plain Song, with an authentic/plagal example like:
And because that is a bit unclear visually what tones are being labeled, here is another version...
Helmore then gives a harmonization...
...it isn't clear which part would represent the chant, I assume it's the scale in the soprano, because it goes
G like the example of the mode with solfege labels. To me, that looks like the final, the
C is in the bass, and the
G in the soprano, the melody, is
SOL, the fifth of the scale, and so a "plagal" chant - melody - would end on
SOL, end on the fifth of the scale.
And then finally an actual piece of Renaissance music which an editor labeled hypoionian...
...this matches up with the two unharmonized examples of the mode. I assume the final is
G, and it's plagal hypoionian, because it moves above and below the final (in this case it conveniently goes to the upper/lower
SOL like the examples, although I understand that isn't always the case in actual compositions.) But, clearly it ends with both bass and melody on
DO so there is no question whether ending on
SOL is the reason it's labeled hypoionian.
The Helmore and Goudimel (or the Goudimel editor's) examples seem to contradict each other. One seems to say plagal means ending on the fifth of the mode
SOL and the other shows ending on
DO but moving above and below the ending tone.
Here are two other examples but in phrygian...
...I truncated the Goudimel but there is enough to see the start and end.
The two are essentially the same musically but the are labeled differently: Helmore says hypophrygian for ending on
^5 but Goudimel says phrygian. They seem to be labeling things opposite.
Can someone clear up what's going on between these two sources?
I would really like a good reference source of actual Renaissance music with the modes properly labeled. If the Goudimel examples are good, then I'll use them. But then why does Helmore seem to be so different?
My original question was about possibly applying the term "plagal" to describe melodies that are not modal Renaissance.
An example from The Revivalist hymnal in a clearly major key where the melody starts and ends on
My understanding - which could be wrong - is melodies that start/end on the fifth of the (authentic) modes are called "plagal" and the mode name gets prefixed with "hypo". So, for example mixolydian, key signature of no sharps/flats, starts and ends on
G, but its plagal form start and ends on
D and the mode is then called hypomixolydian.
This Wikipedia page suggest it could be called hypoionian, but the discussion seems to say that was a theoretical idea of one person in the Renaissance and possibly not in line with even the modal conventions of that time.
Either way, this music clearly isn't modal music. So, is calling this melody, the soprano part, "plagal" inappropriate?
This was just a related add on question.
Similarly, some melodies start/end on the mediant, like The First Noel. Gjerdingen has a phrase schema called Pastorella that outlines
MI RE FA MI. So, I thought such melodies could be called "pastoral", but I doubt anyone would understand the intended meaning. Is there some other common terms to use?