Margo Schulter
2004-01-07 03:50:31 UTC
Hello, there, Cait and everyone.
Some discussions we've recently had on medieval sonorities and
instrumental techniques raise for me an interesting question: the
techniques of crafting a polyphonic texture, whether through
composition or improvisation.
In considering what kinds of polyphonic textures might have been
produced by instrumentalists, either in ensemble improvisations or in
performances on a single instrument, what is known about polyphonic
sonorities and their crafting in composed music might serve as a
possible starting point.
Here the availability of new or more thoroughly published sources, as
well as contributions to the analytical literature over the past four
decades and more by scholars such as Richard Crocker and Sarah Fuller,
permit an approach to written polyphony that might at least set the
question of improvised ensemble or solo instrumental polyphony in a
different context.
In speaking of "improvised instrumental polyphony," I include
accompaniments to monophonic songs as well as purely instrumental
music.
Before delving into some concepts regarding polyphonic sonorities, I
should observe that certain composed repertories have been proposed as
possibly derivative, or representative, of what some improvised
performances may have sounded like.
Most obviously, a 14th-century keyboard source such as the
Robertsbridge Codex suggests a style that keyboard players might have
followed either in adopting a vocal composition such as an Ars Nova
motet for solo performance, or for improvising part music based on
some kind of estampie genre like the dances in this collection. It has
been proposed that players of such instruments as the gittern might
look to the early keyboard sources in seeking out possible polyphonic
techniques for a late medieval milieu.
Additionally, certain genres of texted 13th-14th century polyphony
have been proposed as reflecting elements of styles involving
improvised instrumental accompaniment. Thus two-voice French motets in
the Codex Montpellier have been described as accompanied songs, and it
has been suggested by Richard Hoppin that the three-voice rondeaux of
Adam de la Halle might reflect techniques used in improvised
instrumental accompaniments.
Also, Hoppin proposes that the early 14th-century Italian madrigal
repertory, while some have compared it to the technique of the earlier
conductus, might more likely have developed "from secular monophony
with an improvised accompaniment."
Whatever "models" one considers for improvised instrumental polyphony,
there is the interesting question of how polyphonic sonorities and
their crafting were conceived of in composed polyphony, and how such
conceptions might have either influenced or been modified in
improvisatory textures, especially for a solo instrument such as the
organ or harp, or possibly a fretted instrument such as the citole or
gittern, for example.
------------------------------------------------------
1. Medieval sonority: neither random nor prefabricated
------------------------------------------------------
Two notions often influence modern scholarship regarding vertical
sonorities and progressions in medieval European polyphony. Either the
music represents a nascent if often inept or frustrated striving to
write "good harmony" according to 18th-19th century triadic rules; or
else it represents a "linear technique" in which vertical sonorities
result mainly as a "coincidence" of melodic lines.
However, both the music itself and some vital writings about
multi-voice sonorities from around 1300 and a bit later admit of
another perspective which I would like to present here.
In this alternative view, multi-voice sonorities in 13th-14th century
polyphony are neither random coincidences of the parts, nor the result
of a "prefabricated" chordal technique like that might be used to
fashion a 19th-century piano or guitar accompaniment in a major/minor
tonal style.
Rather we should consider such medieval concepts as the complete
trine, layered composition, the building of stable or unstable
multi-voice sonorities through partition or joining of intervals (to
be explained shortly), and sometimes differing preferences as to which
sonorities for three or more voices are pleasing or otherwise.
On the last point, theorists around 1300 are quite capable not only of
describing simultaneous sonorities for three or more voices, but of
expressing their preferences. Thus Jacobus of Liege (c. 1325) strongly
recommends a mildly unstable with an outer major ninth formed from two
euphonious fifths (e.g. D3-A3-E4, with C4 here showing middle C),
while a treatise from the same era "according to Johannes de Muris"
specifically cautions against this same sonority, rejecting the ninth
as "dissonant."
Both Jacobus and Johannes de Muris (or his student) agree that _all_
intervals in a recognized multi-voice sonority must be acceptably
concordant, but differ on whether the major ninth is to be regarded as
a partial concord or an outright discord. Additionally Jacobus,
reflecting the taste of his youth in the later 13th century, finds
that the outer major ninth "seems better to concord" when combined
with the two ideally concordant fifths; the "modern" Ars Nova treatise
may lean more toward sonorities with thirds or sixths.
Whatever stylistic implications such a dialogue might have -- and
Machaut, I would say, seems to agree with Jacobus about the major
ninth sonority and with Johannes de Muris or his disciple about a
greater emphasis on thirds and sixths -- it hardly seems
characteristic of a milieu where musicians are incapable of conceiving
three-voice simultaneities, or indifferent to overall vertical
euphony.
If we agree that multi-voice sonorities are relevant, then where do we
start in considering their crafting and use either in the notated
polyphonic repertory known to us, or in improvisatory instrumental
textures or accompaniments?
-------------------------------------------------------
2. Grocheio: The complete trine and layered composition
-------------------------------------------------------
A good starting point is provided by Johannes de Grocheio, who
explains that complete harmony or concord requires _three_ voices
forming a sonority I will call a _trine_ (from the _trina harmoniae
perfectio_ or "threefold perfection of harmony" which this sonority
manifests). This perfect harmony consists of an outer octave, lower
fifth, and upper fourth (e.g. D3-A3-D4).
One modern notation for indicating this vertical structure, 1-5-8,
could fit Grocheio's exposition of three-voice compositional
technique. One starts with the tenor, like the foundation of a house,
in building the musical edifice. Then one adds a duplum or motetus,
typically at a fifth above the tenor; followed by a triplum, typically
at an octave above the tenor. Together, these voices in their typical
dispositions form a trine, or _consonantia perfectissima_ as Grocheio
calls it, noting that it requires three voices to "perfect" this ideal
concord.
He also notes that the upper voices often cross and exchange roles,
explaining that a quadruplum or fourth voice is sometimes added, and
can help in perfecting the consonance (i.e. completing a trine) if
other voices are at a unison, or "truncate each other" (as in
hocketing, which he also describes).
Thus Grocheio expounds a layered process for building up a complex
texture in measured polyphony, as with a conductus, motet, or hocket:
first the tenor or foundation, then the duplum or motetus, and then
the triplum, with an optional quadruplum which can make possible more
consistently complete trinic concord.
This account, focusing mainly on rich and complete stable harmony,
suggests some possible techniques either for accompanying a monophonic
song on a harp or gittern, for example, or for improvising a solo
polyphonic texture. One might simply seek to add trines to the melody
at stategic points -- or possibly a drone, on the final or moveable --
or develop more intricate idioms involving contrasts between stability
and directed instability.
For example, consider a trine-to-fifth-to-trine figure like this, with
the melody in the upper part:
1 2 3 | 1 2 3 | 1
Melody: F4 E4 D4 E4 F4
C4 D4 C4
Accompaniment: F3 G3 F3
Here we open with the complete trine F3-C4-F4, with the momentary
seventh combination F3-C4-E4 contracting to the fifth G3-D4, followed
by the momentary sixth combination G3-D4-E4 expanding back to the
trine on F. While the unstable sonorities are quite transient, they
introduce a pleasant element of contrast to the harmonic rhythm:
concord at the opening of a rhythmic unit, and directed tension at the
end of a unit moving us forward toward the next stable concord.
We might also briefly note that the resolution of the major seventh
combination involves two elementary two-voice resolutions by stepwise
contrary motion (Maj7-5 + Maj3-1), as does also the later resolution
of the major sixth combination (Maj6-8 + Maj2-4).
Often, as here, this kind of texture might almost "write itself" --
and my example is based on the opening of a Montpellier motet -- or,
in improvisation, flow as it were out of the process of adding some
judicious concords to a melody. The accompanying instrument plays a
texture of simple fifths, with the melody moving above them in
contrary motion. One could also, of course, improvise all three voices
on a suitable instrument.
-----------------------------------
3. Jacobus: Partitions and joinings
-----------------------------------
While Grocheio tells us a great deal about the stable trine and its
role in composition, what about unstable sonorities? Here Jacobus of
Liege gives us invaluable help both in appreciating the musical use of
these sonorities, and in seeking ways to describe and notate their
structure which might be more congenial to medieval practice and
theory.
For Jacobus, a sonority of three or more voices can be described as a
"partition" (_partition_) or "splitting" (_fissio_) of an outer
interval into two or more adjacent intervals. A 1-5-8 trine, D3-A3-D4
for example, consists of an octave "split" into a fifth below and
fourth above.
To express this concept compactly in ASCII text, we might write
8|5_4
which can be read: "an outer octave partitioned or split into lower
fifth and upper fourth."
The same approach applies to unstable sonorities. Let us consider the
major sixth sonority of the three-voice passage above, G3-D4-E4.
Jacobus describes this type of partition or multi-voice sonority as a
major sixth split into fifth below and major second above, all
acceptably compatible intervals. Thus we have
M6|5_M2
This sonority is common in 13th-century writing, and also sometimes
used prominently by Machaut, but less favored by Ars Nova theorists
who regard the major second as an outright and full discord. For
Jacobus, as for some earlier theorists going back to Guido, however,
it has some degree of "compatibility," and so is a legitimate element
of recognized combinations.
In contrast, the other transient unstable sonority in our sample
passage, F3-C4-E4, would not be included in the catalogue of
partitions which Jacobus has provided, since he classifies the outer
major seventh as an outright discord. He specifically cautions that
two concordant intervals such as the fifth and major third can form a
discord such as the major seventh, so that one must take into account
_all_ intervals.
However, bold as well as more transient major seventh combinations are
found in 13th-century pieces, and we can notate this structure as an
outer major seventh split into lower fifth and upper major third, or
M7|5_M3
Now the question arises: all this is very interesting, but how might
it tie in with compositional, or possibly also improvisational,
technique? Jacobus himself tells us that partitions can be helpful in
making discant, which could mean either composed or improvised
polyphony.
If we assume a layered compositional technique of the kind described
by theorists such as Franco and Grocheio, then the applicability is
easy to see in a situation like this, where one is adding a triplum to
a two-voice texture:
E4 F4
G3 F3
Suppose that this is a cadence, or at any rate a point where we wish
to have a three-voice texture amplifying the Maj6-8 resolution from
instability to stability. Here knowing about the ideal stable trine,
and about some partitions of the octave and major sixth, can help us
in exploring some different solutions.
For example, the most common solution is this:
Triplum: B3 C4
Motetus: E4 F4
Tenor: G3 F3
M6|M3_4 8|5_4
Here the triplum splits the unstable major sixth into lower major
third and upper fourth, a partition included in the catalogue of
Jacobus, and then splits the resolving octave into the lower fifth and
upper fourth of a complete trine. In addition to filling out the
texture, this new part also has an excellent two-voice resolution of
its own with the lowest voice: Maj3-5.
Another solution, also typical of the 13th century and sometimes used
by Machaut as well as by certain English composers of the 14th-century
era, uses a different partition of the major sixth also, as noted
above, catalogued by Jacobus:
Triplum: D4 C4
Motetus: E4 F4
Tenor: G3 F3
M6|5_M2 8|5_4
In this kind of situation, the partition concept applies most
directly: our third voice "splits" an outer interval already formed by
the first two voices.
In other situations, another concept presented by Jacobus is helpful:
"joining" two adjacent intervals so as to form a new outer interval.
For example, let us consider this two-voice close:
1 2 3 | 1
C4 B3 C4
G3 F3
One colorful three-voice solution is this:
1 2 3 | 1
Triplum: D4 E4 F4
Motetus: C4 B3 C4
Tenor: G3 F3
5|4_M2 M6|M3_4 8|5_4
In the first sonority, the triplum adds an upper major second C4-D4
"joined" to the lower fourth G3-C4 so as to form an outer fifth G3-D4,
or a partition of 5|4_M2, catalogued by Jacobus.
In the penultimate cadential sonority, the triplum joins an upper
fourth B3-E4 to the lower major third G3-B3, forming the outer major
sixth G3-E4 -- a partition of M6|M3_4. This sonority resolves to a
complete trine on F, 8|5_4, where the triplum joins an upper fourth
C4-F4 to the lower fifth F3-C4, forming the outer octave of the trine.
We could also focus on the outer intervals formed by the tenor-triplum
pair and the partitions made by the motetus. Thus the first note of
the triplum forms the fifth G3-D4 with the tenor, split by the motetus
into 5|4_M2; the penultimate note forms the major sixth G3-E4, split
into M6|M3_4, and the last note the octave F3-F4, split into 8|5_4.
Thus the concepts of "partition" and "joining" of intervals provide a
model for how one can build up a musical texture in layers while
taking account of the sonorities generated in the process.
While the question of whether and how experienced composers from
Perotin to Ciconia may have conceived of their voices successively or
sometimes simultaneously is an intriguing one, my main point here has
been that successive composition does not necessarily imply
indifference to the vertical dimension in general or to multi-voice
sonorities in particular.
A concept of partition or the like, not necessarily articulated in a
formal theoretical manner like that of the encyclopedic Jacobus, might
also inform the technique of a 13th-century or 14th-century harpist,
for example, improvising a three-voice texture. Familiarity with
stable trines and with some unstable sonorities or partitions of an
outer fifth, sixth, and seventh, etc., and of typical resolutions,
could provide a ready basis for extempore solo polyphony.
My purpose here is to propose one starting point for considering what
improvising instrumentalists _might_ have done if pursuing polyphonic
styles influenced by or also quite possibly influencing the written
compositions of the 13th-14th century era.
Warmly thanking Cait and others, I invite discussion on specific
instruments or possible performance traditions in either a solo or
ensemble setting.
Most appreciatively,
Margo Schulter
***@calweb.com
Some discussions we've recently had on medieval sonorities and
instrumental techniques raise for me an interesting question: the
techniques of crafting a polyphonic texture, whether through
composition or improvisation.
In considering what kinds of polyphonic textures might have been
produced by instrumentalists, either in ensemble improvisations or in
performances on a single instrument, what is known about polyphonic
sonorities and their crafting in composed music might serve as a
possible starting point.
Here the availability of new or more thoroughly published sources, as
well as contributions to the analytical literature over the past four
decades and more by scholars such as Richard Crocker and Sarah Fuller,
permit an approach to written polyphony that might at least set the
question of improvised ensemble or solo instrumental polyphony in a
different context.
In speaking of "improvised instrumental polyphony," I include
accompaniments to monophonic songs as well as purely instrumental
music.
Before delving into some concepts regarding polyphonic sonorities, I
should observe that certain composed repertories have been proposed as
possibly derivative, or representative, of what some improvised
performances may have sounded like.
Most obviously, a 14th-century keyboard source such as the
Robertsbridge Codex suggests a style that keyboard players might have
followed either in adopting a vocal composition such as an Ars Nova
motet for solo performance, or for improvising part music based on
some kind of estampie genre like the dances in this collection. It has
been proposed that players of such instruments as the gittern might
look to the early keyboard sources in seeking out possible polyphonic
techniques for a late medieval milieu.
Additionally, certain genres of texted 13th-14th century polyphony
have been proposed as reflecting elements of styles involving
improvised instrumental accompaniment. Thus two-voice French motets in
the Codex Montpellier have been described as accompanied songs, and it
has been suggested by Richard Hoppin that the three-voice rondeaux of
Adam de la Halle might reflect techniques used in improvised
instrumental accompaniments.
Also, Hoppin proposes that the early 14th-century Italian madrigal
repertory, while some have compared it to the technique of the earlier
conductus, might more likely have developed "from secular monophony
with an improvised accompaniment."
Whatever "models" one considers for improvised instrumental polyphony,
there is the interesting question of how polyphonic sonorities and
their crafting were conceived of in composed polyphony, and how such
conceptions might have either influenced or been modified in
improvisatory textures, especially for a solo instrument such as the
organ or harp, or possibly a fretted instrument such as the citole or
gittern, for example.
------------------------------------------------------
1. Medieval sonority: neither random nor prefabricated
------------------------------------------------------
Two notions often influence modern scholarship regarding vertical
sonorities and progressions in medieval European polyphony. Either the
music represents a nascent if often inept or frustrated striving to
write "good harmony" according to 18th-19th century triadic rules; or
else it represents a "linear technique" in which vertical sonorities
result mainly as a "coincidence" of melodic lines.
However, both the music itself and some vital writings about
multi-voice sonorities from around 1300 and a bit later admit of
another perspective which I would like to present here.
In this alternative view, multi-voice sonorities in 13th-14th century
polyphony are neither random coincidences of the parts, nor the result
of a "prefabricated" chordal technique like that might be used to
fashion a 19th-century piano or guitar accompaniment in a major/minor
tonal style.
Rather we should consider such medieval concepts as the complete
trine, layered composition, the building of stable or unstable
multi-voice sonorities through partition or joining of intervals (to
be explained shortly), and sometimes differing preferences as to which
sonorities for three or more voices are pleasing or otherwise.
On the last point, theorists around 1300 are quite capable not only of
describing simultaneous sonorities for three or more voices, but of
expressing their preferences. Thus Jacobus of Liege (c. 1325) strongly
recommends a mildly unstable with an outer major ninth formed from two
euphonious fifths (e.g. D3-A3-E4, with C4 here showing middle C),
while a treatise from the same era "according to Johannes de Muris"
specifically cautions against this same sonority, rejecting the ninth
as "dissonant."
Both Jacobus and Johannes de Muris (or his student) agree that _all_
intervals in a recognized multi-voice sonority must be acceptably
concordant, but differ on whether the major ninth is to be regarded as
a partial concord or an outright discord. Additionally Jacobus,
reflecting the taste of his youth in the later 13th century, finds
that the outer major ninth "seems better to concord" when combined
with the two ideally concordant fifths; the "modern" Ars Nova treatise
may lean more toward sonorities with thirds or sixths.
Whatever stylistic implications such a dialogue might have -- and
Machaut, I would say, seems to agree with Jacobus about the major
ninth sonority and with Johannes de Muris or his disciple about a
greater emphasis on thirds and sixths -- it hardly seems
characteristic of a milieu where musicians are incapable of conceiving
three-voice simultaneities, or indifferent to overall vertical
euphony.
If we agree that multi-voice sonorities are relevant, then where do we
start in considering their crafting and use either in the notated
polyphonic repertory known to us, or in improvisatory instrumental
textures or accompaniments?
-------------------------------------------------------
2. Grocheio: The complete trine and layered composition
-------------------------------------------------------
A good starting point is provided by Johannes de Grocheio, who
explains that complete harmony or concord requires _three_ voices
forming a sonority I will call a _trine_ (from the _trina harmoniae
perfectio_ or "threefold perfection of harmony" which this sonority
manifests). This perfect harmony consists of an outer octave, lower
fifth, and upper fourth (e.g. D3-A3-D4).
One modern notation for indicating this vertical structure, 1-5-8,
could fit Grocheio's exposition of three-voice compositional
technique. One starts with the tenor, like the foundation of a house,
in building the musical edifice. Then one adds a duplum or motetus,
typically at a fifth above the tenor; followed by a triplum, typically
at an octave above the tenor. Together, these voices in their typical
dispositions form a trine, or _consonantia perfectissima_ as Grocheio
calls it, noting that it requires three voices to "perfect" this ideal
concord.
He also notes that the upper voices often cross and exchange roles,
explaining that a quadruplum or fourth voice is sometimes added, and
can help in perfecting the consonance (i.e. completing a trine) if
other voices are at a unison, or "truncate each other" (as in
hocketing, which he also describes).
Thus Grocheio expounds a layered process for building up a complex
texture in measured polyphony, as with a conductus, motet, or hocket:
first the tenor or foundation, then the duplum or motetus, and then
the triplum, with an optional quadruplum which can make possible more
consistently complete trinic concord.
This account, focusing mainly on rich and complete stable harmony,
suggests some possible techniques either for accompanying a monophonic
song on a harp or gittern, for example, or for improvising a solo
polyphonic texture. One might simply seek to add trines to the melody
at stategic points -- or possibly a drone, on the final or moveable --
or develop more intricate idioms involving contrasts between stability
and directed instability.
For example, consider a trine-to-fifth-to-trine figure like this, with
the melody in the upper part:
1 2 3 | 1 2 3 | 1
Melody: F4 E4 D4 E4 F4
C4 D4 C4
Accompaniment: F3 G3 F3
Here we open with the complete trine F3-C4-F4, with the momentary
seventh combination F3-C4-E4 contracting to the fifth G3-D4, followed
by the momentary sixth combination G3-D4-E4 expanding back to the
trine on F. While the unstable sonorities are quite transient, they
introduce a pleasant element of contrast to the harmonic rhythm:
concord at the opening of a rhythmic unit, and directed tension at the
end of a unit moving us forward toward the next stable concord.
We might also briefly note that the resolution of the major seventh
combination involves two elementary two-voice resolutions by stepwise
contrary motion (Maj7-5 + Maj3-1), as does also the later resolution
of the major sixth combination (Maj6-8 + Maj2-4).
Often, as here, this kind of texture might almost "write itself" --
and my example is based on the opening of a Montpellier motet -- or,
in improvisation, flow as it were out of the process of adding some
judicious concords to a melody. The accompanying instrument plays a
texture of simple fifths, with the melody moving above them in
contrary motion. One could also, of course, improvise all three voices
on a suitable instrument.
-----------------------------------
3. Jacobus: Partitions and joinings
-----------------------------------
While Grocheio tells us a great deal about the stable trine and its
role in composition, what about unstable sonorities? Here Jacobus of
Liege gives us invaluable help both in appreciating the musical use of
these sonorities, and in seeking ways to describe and notate their
structure which might be more congenial to medieval practice and
theory.
For Jacobus, a sonority of three or more voices can be described as a
"partition" (_partition_) or "splitting" (_fissio_) of an outer
interval into two or more adjacent intervals. A 1-5-8 trine, D3-A3-D4
for example, consists of an octave "split" into a fifth below and
fourth above.
To express this concept compactly in ASCII text, we might write
8|5_4
which can be read: "an outer octave partitioned or split into lower
fifth and upper fourth."
The same approach applies to unstable sonorities. Let us consider the
major sixth sonority of the three-voice passage above, G3-D4-E4.
Jacobus describes this type of partition or multi-voice sonority as a
major sixth split into fifth below and major second above, all
acceptably compatible intervals. Thus we have
M6|5_M2
This sonority is common in 13th-century writing, and also sometimes
used prominently by Machaut, but less favored by Ars Nova theorists
who regard the major second as an outright and full discord. For
Jacobus, as for some earlier theorists going back to Guido, however,
it has some degree of "compatibility," and so is a legitimate element
of recognized combinations.
In contrast, the other transient unstable sonority in our sample
passage, F3-C4-E4, would not be included in the catalogue of
partitions which Jacobus has provided, since he classifies the outer
major seventh as an outright discord. He specifically cautions that
two concordant intervals such as the fifth and major third can form a
discord such as the major seventh, so that one must take into account
_all_ intervals.
However, bold as well as more transient major seventh combinations are
found in 13th-century pieces, and we can notate this structure as an
outer major seventh split into lower fifth and upper major third, or
M7|5_M3
Now the question arises: all this is very interesting, but how might
it tie in with compositional, or possibly also improvisational,
technique? Jacobus himself tells us that partitions can be helpful in
making discant, which could mean either composed or improvised
polyphony.
If we assume a layered compositional technique of the kind described
by theorists such as Franco and Grocheio, then the applicability is
easy to see in a situation like this, where one is adding a triplum to
a two-voice texture:
E4 F4
G3 F3
Suppose that this is a cadence, or at any rate a point where we wish
to have a three-voice texture amplifying the Maj6-8 resolution from
instability to stability. Here knowing about the ideal stable trine,
and about some partitions of the octave and major sixth, can help us
in exploring some different solutions.
For example, the most common solution is this:
Triplum: B3 C4
Motetus: E4 F4
Tenor: G3 F3
M6|M3_4 8|5_4
Here the triplum splits the unstable major sixth into lower major
third and upper fourth, a partition included in the catalogue of
Jacobus, and then splits the resolving octave into the lower fifth and
upper fourth of a complete trine. In addition to filling out the
texture, this new part also has an excellent two-voice resolution of
its own with the lowest voice: Maj3-5.
Another solution, also typical of the 13th century and sometimes used
by Machaut as well as by certain English composers of the 14th-century
era, uses a different partition of the major sixth also, as noted
above, catalogued by Jacobus:
Triplum: D4 C4
Motetus: E4 F4
Tenor: G3 F3
M6|5_M2 8|5_4
In this kind of situation, the partition concept applies most
directly: our third voice "splits" an outer interval already formed by
the first two voices.
In other situations, another concept presented by Jacobus is helpful:
"joining" two adjacent intervals so as to form a new outer interval.
For example, let us consider this two-voice close:
1 2 3 | 1
C4 B3 C4
G3 F3
One colorful three-voice solution is this:
1 2 3 | 1
Triplum: D4 E4 F4
Motetus: C4 B3 C4
Tenor: G3 F3
5|4_M2 M6|M3_4 8|5_4
In the first sonority, the triplum adds an upper major second C4-D4
"joined" to the lower fourth G3-C4 so as to form an outer fifth G3-D4,
or a partition of 5|4_M2, catalogued by Jacobus.
In the penultimate cadential sonority, the triplum joins an upper
fourth B3-E4 to the lower major third G3-B3, forming the outer major
sixth G3-E4 -- a partition of M6|M3_4. This sonority resolves to a
complete trine on F, 8|5_4, where the triplum joins an upper fourth
C4-F4 to the lower fifth F3-C4, forming the outer octave of the trine.
We could also focus on the outer intervals formed by the tenor-triplum
pair and the partitions made by the motetus. Thus the first note of
the triplum forms the fifth G3-D4 with the tenor, split by the motetus
into 5|4_M2; the penultimate note forms the major sixth G3-E4, split
into M6|M3_4, and the last note the octave F3-F4, split into 8|5_4.
Thus the concepts of "partition" and "joining" of intervals provide a
model for how one can build up a musical texture in layers while
taking account of the sonorities generated in the process.
While the question of whether and how experienced composers from
Perotin to Ciconia may have conceived of their voices successively or
sometimes simultaneously is an intriguing one, my main point here has
been that successive composition does not necessarily imply
indifference to the vertical dimension in general or to multi-voice
sonorities in particular.
A concept of partition or the like, not necessarily articulated in a
formal theoretical manner like that of the encyclopedic Jacobus, might
also inform the technique of a 13th-century or 14th-century harpist,
for example, improvising a three-voice texture. Familiarity with
stable trines and with some unstable sonorities or partitions of an
outer fifth, sixth, and seventh, etc., and of typical resolutions,
could provide a ready basis for extempore solo polyphony.
My purpose here is to propose one starting point for considering what
improvising instrumentalists _might_ have done if pursuing polyphonic
styles influenced by or also quite possibly influencing the written
compositions of the 13th-14th century era.
Warmly thanking Cait and others, I invite discussion on specific
instruments or possible performance traditions in either a solo or
ensemble setting.
Most appreciatively,
Margo Schulter
***@calweb.com