How is a clausula tertiaria/medians distinguished from a modulation to the relative major?

Clausula tertiaria came up in the answer to one of my earlier questions.

Some of the definitions I have found include:

  • demi-cadence effected upon the third of the key
  • cadence on the third, in a piece in the minor mode
  • cadence of a piece in a minor key, when it took place in the key of the third

None are illustrated with notation.

Only the third definition listed speaks of a change in key.

From a modern, harmonic perspective, a move to the relative major can be purely diatonic and has the tendency to sound like a modulation. From that perspective does that mean a clausula tertiaria and modulation to the relative major are indistinguishable?

The terminology is clouded by historical usage, translation, and the evolution of tonality. This article, Theory Ruled by Practice, has a quote on the second page referencing Zarlino, the cadence tertiaria, and suggesting it is all speculative. But the rest of the article doesn't seem to have anything specifically about the clausula tertiaria.

Can anyone explain this cadence more clearly? A notated example would be idea.

1 Answer 1


I believe the concept of the clausula tertiaria originated in Zarlino, or at least he was the one who popularized the notion. For Zarlino, cadences had nothing to do with harmony or chords, let alone keys. The term clausula is often translated as "cadence," but the notion of what constituted a "cadence" changed a lot over the centuries.

For Zarlino, a stereotypical clausula followed the standard clausula vera formula, which was a two-voice structure, generally looking something like the end of this example from Lassus:

Clausula vera

Note the descending stepwise motion in the lower (tenor) voice, with a suspension in the upper voice moving in an 8-7-8 pattern above the tenor 2-1 motion. Musica ficta was typically employed in the upper part (i.e., the sharp here) to create a major sixth, except in Phrygian motions where the "leading tone" was found in the semitone descent in the bass.

The particular motions of the voices at times were labeled with specific names, e.g., the clausula tenorizans which consisted of a descending stepwise motion like a typical tenor part, and the clausula cantizans, which was the 8-7-8 motion with suspension seen here, as typically would appear in a cantus or upper voice part. (The examples and video on this page give a pretty reasonable introduction to how these early clausula formula were seen as composed of individual stereotypical voice motions. Eventually, there were stereotypical motions named for the bassus and altus parts too which could optionally be added at a cadence, but the true cadence until the 17th century at least was the two-voice structure seen above.)

For Zarlino, this outward motion of a sixth to octave in two voices, typically with suspension, was a clausula. There's no other implication of harmony, chords, key, modulation, etc. which were all concepts that developed with later theory.

Zarlino was probably the first theorist to propose a system for which pitches were most typical for cadences (clausulae) in a given mode. In general, the primary cadences were to the modal final. Note again that we're just looking at this two-voice structure. In a piece with more than two parts, any occurrence of the clausula vera motion in any two paired voices could theoretically constitute a clausula in Zarlino's terms.

Zarlino then added a concept that "secondary" cadences in a mode occurred on the fifth above the final, and "tertiary" cadences occurred a third above the final. Hence the clausula tertiaria. (Any other cadence to any other note was considered a clausula peregrina, i.e., a "wandering cadence.") Cadences could be identified clearly with even one voice part, so musical examples in historical treatises often only showed one or two parts, as in this example (from this article) from a 1687 treatise by Ahle, which follows Printz who followed Calvisius who followed Zarlino, in the treatment of cadences:

Proper Cadences

Note the syncopation that implied the upper-voice suspension of the clausula cantizans. The tenor voice motion that would go with such melodies could be assumed. (Also, note that these motions could certainly be inverted: the clausula tenorizans could happen in voices other than the tenor, and you might end up with a third moving in contrary motion to a unison, or a tenth moving to an octave, etc.)

So, at the time when terms like clausula tertiaria or medians were being actively used, this was the conception of a cadence. It mostly implied a 6-8 intervallic contrary motion in two voices, usually with suspension. The clausula tertiaria merely happened on a note that was a third above the final of a mode. No further implications of harmony or chords or key were necessarily connected.

Which is not to say that one couldn't have other voices creating a better sense of harmony, of course. Here's an example from a 1643 treatise by Herbst (from this article), showing the three standard cadence types for a mode based on E:

Herbst example

Herbst uses alternate terminology from the primaria, secundaria, tertiaria, instead labeling the cadences principalis, minus principalis, and affinalis, respectively. But the implications were the same as the three-fold Zarlinian classification.

Note the clausula vera pattern occurring in the upper voice and the tenor -- that was the primary "cadence." The harmonies were incidental and conformed to the local scale. As seen here, for example, the principalis cadence would actually be what we'd nowadays call a "plagal" cadence to A, due to the Phrygian mode and semitone motion in the tenor. But the modal final -- the primary destination note of this cadence -- was seen to be E, as in the F-E motion of the tenor part.

The "secondary" cadence (minus principalis) on the fifth scale degree required a similar accommodation for this mode, arriving on B in the tenor but looking like a modern plagal cadence in E minor. The "tertiary" cadence, which occurred on G, a third above E, looks more like our modern "authentic" cadence to "G major," but that's just because of where it fell in the scale. If we looked at patterns of cadences in a mode with a final of G, for example, the clausula tertiaria would typically look like the "plagal" Phrygian formulas seen here going to a B in the tenor (which would look like a plagal cadence to E in modern terms).

From the perspective of modern harmony in these four-part versions, this all seems quite confusing in terms of "key." While a D-based mode would have a final cadence to a D minor triad and a clausula tertiaria that would effectively be like a modern authentic cadence in F major, that's clearly only one possibility. The E-based mode here tends to cadence to an A major (or minor) triad with a plagal motion, with the clausula tertiaria going to G major. An F-based mode would cadence to F major, with a clausula tertiaria as an authentic cadence motion in A minor, but a G-based mode would cadence with G major, with a clausula tertiaria as a plagal cadence that in a modern sense would look like arriving at E minor.

From a modern harmonic analysis standpoint that sees root of chord rather than tenor as the foundation of harmony, and if we take the primary cadence of the mode with its concluding chord as the basis of the "key," then a clausula tertiaria in modern terms -- harmonized in standard four-part fashion -- could conclude on III or VII or iii or vi, depending on which final you choose.

But that's not the end of the story. As we see in the Herbst example, he adds a "finalis" cadence arriving on an E major triad, as the plagal motion to A major or A minor seen in the principalis cadences perhaps doesn't seem to emphasize the modal final of E. Here we can see the 17th-century tension between the older modal conceptions of cadences as melodic features with the emerging harmonic backdrop that wants E to be emphasized not just in tenor but as a root of the sonority in a truly final cadence of a piece. (This is only necessary in E final or Phrygian modes.)

There are other possible harmonizations as well as inconsistencies in terminology usage among treatises. And 17th-century treatises sometimes started to avoid plagal and Phrygian cadences through the introduction of more chromaticism (like F♯ in the tenor line to create a F♯-E motion and avoid a Phrygian or plagal cadence). So I'm pretty sure you can find some other options for various finals as modes gradually shifted toward modern key ideas and transpositions over the 1600s.

From a modern, harmonic perspective, a move to the relative major can be purely diatonic and has the tendency to sound like a modulation. From that perspective does that mean a clausula tertiaria and modulation to the relative major are indistinguishable?

Well, given the vastly different perspectives that these notions of cadence are derived from, it's very difficult to claim they are "indistiguishable." The clausula tertiaria was grounded in melodic motions ultimately created around the two-voice clausula vera structure, and any implications of chords or harmony came from where in the traditional scale/gamut it happened to fall. In some cases for particular modes (like D and A finals), an anachronistic analysis of some cadences might look like a motion to the relative major, in the modern sense. But the idea of "modulation to the relative major" wasn't really possible until the key conceptions and tonality of the 18th century, when terms like clausula tertiaria were falling out of use.

I suppose maybe the question is asking whether there's some historical relationship between the two? Yes, probably. Zarlino and other theorists perhaps emphasized the third above the final as a destination for cadences because music in certain modes -- like those based on D or A -- was already frequently doing it. (I don't know off-hand how far back this goes, but I feel like I could easily find pieces from the early 1500s -- decades before Zarlino's treatise -- that have a final with a minor third above it and frequently move toward cadences on that note a third above the final.)

There's certainly not a one-to-one correspondence between the modal clausulae and modern modulatory cadences, though they do share the use of leading tones (previously musica ficta) and sometimes patterns to frequency of cadences which preceded the ultimate tonal modulations like I to V in major keys and i to III in minor keys.

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