Pretty Saro in D tuning: What key and mode?

This is a long reply to Julie Elman's question about the key and mode of Pretty Saro when it is played in D tuning. B. Ross Ashley gave some excellent responses to Julie's question, and I don't disagree with anything he said. I will come at the question from a slightly different direction. Here's Julie's question.


Ill start, because it often comes up in discussions of this sort, by saying that no-one thinks that the folk musicians of yesteryear made any of the delicate distinctions discussed below. What follows is a discussion among moderns about how best to categorize a tune. Also I'm using ecclesiastical rather than Greek mode definitions.

All that said, most folk tunes end on the tonic of the key in which you're playing. If you're playing in the key of D, the tune ends on a D note. A minority of folk tunes end on the dominant, which in the key of D is an A note, and I would argue that Pretty Saro is one of those songs. Here's a LINK to a fasola group discussion of several shape note tunes that end on the dominant, and there as here, the question arises as to whether the songs are in Mixolydian mode (or at least were at some point in the past). Continuing with our example in the key of D, the question always arises as to whether such tunes are actually in the key of A. If we had an ironclad rule that tunes always end on the tonic, then we would have to say, "Yes, it's a tune in the key of A".

(In my view this is true whether we play it in DAA or DAD tuning. The notes are the same in either tuning.)

In the case of Pretty Saro, two problems arise if we consider it to be a Mixolydian tune (which would, of necessity, be in the key of A).

The first is that Pretty Saro is a pentatonic tune, lacking the fourth and seventh scale degrees. Thus, there's no seventh scale degree to be flatted. Whether the song is in the key of A (ending on the tonic) or in the key of D (ending on the dominant) the most precise statement we can make is that Pretty Saro is consistent with both the Ionian and Mixolydian modes. This is because the Mixolydian mode differs from the Ionian only in the seventh degree (which is natural in the Ionian and flatted in the Mixolydian) and Pretty Saro doesn't contain a seventh.

Suppose (and I will argue this to be the case) that folk tunes don't always end on the tonic. This problem has been discussed since at least the 16th century, and the first detailed discussion of tunes like Pretty Saro is in a treatise entitled Dodecachordon (1547) by the Swiss monk Heinrich Glarean . (But see also Hucbalss De Harmonica , ca 880 AD, which everyone cites, but which no-one, least of all me, has read.)

Glarean added the notion of plagal modes to existing modal theory. (The work "plagal" comes from a Greek root meaning "sideways" or "athwart" because a plagal mode sits "across" a standard mode.) A plagal mode is a mode using the tones of one of the regular ecclesiastical modes, but starting the scale a fourth below the tonic (e.g. on the A note in the key of D). The standard mode starts at the tonic and ends on the seventh. Glarean differentiated plagal modes from the standard modes (which are called "authentic modes") by adding the prefix "hypo-" to the ecclesiastical authentic name.

Glarean noted that each of the plagal ("hypo") modes corresponds an authentic mode in another key. In our case, these would be the Hypoionian mode in the key of D which corresponds to the Mixolydian mode in the Key of A. In each case the scale starts on an A note.

Another way of saying this is that Pretty Saro uses the notes of the Ionian scale in the key of D, but its scale start is at the point on the dulcimer fretboard (the open string) where we would start a Mixolydian scale in the key of A. Under Glarean's classification, I believe that our version of Pretty Saro is a Hypoionian tune in D, thereby using the notes of the Ionian authentic mode while having a scale that starts a fourth below that of the Ionian mode. In our case this puts the scale start on the A note below the tonic. (Which is also and not incidentally the note on which Pretty Saro ends.)

Introducing plagal modes allows us to have a rule that says, "All tunes end on the starting note of their scale" with the understanding that plagal scales start a fourth below the tonic.

It has been noted for centuries that there is a material circularity in this argument. If we don't insist that tunes end on the tonic of their key -- songs in the key of D must end on a D note -- then the question arises as to how we know which key we are in. (In this case D Hypoionian versus A Mixolydian). This has usually been resolved by asking what chord ends the tune. In the case of Pretty Saro in the key of D, everyone I know thinks that the final chord is the (Roman-numeral) I chord, i.e. a D chord.

Similarly, in the shape-note discussion above, every one of the tunes mentioned has a bass part that ends on the tonic. Thus, the chord on which each ends is the I chord. At this point we reach our second difficulty, because the argument becomes somewhat circular.

We are reduced to saying that it's "obvious" that the tune "resolves" to a D chord, because the tune lacks a "sense of resolution" if we try to end it on an A chord. Ending on an A chord "just sounds wrong". The problem here is that there is no universal and precise definition for sense of resolution or "sounds wrong" as it applies to vernacular folk tunes. (Although I believe that most of us would agree that ending a key-of-D version of Pretty Saro with an A chord would "sound wrong".) So I will just say that Pretty Saro, as we discuss it here, is in my opinion best considered as a tune in D Hypoionian rather than in A Mixolydian, allowing for the unavoidable fuzziness in the definition of resolution and the fact that Pretty Saro is a pentatonic tune.

I started investigating this when I worked up the tunes to Faithful Soldier and Hallelujah both of which end on the dominant.

Questions, comments, disagreements welcome.