Although they occupy the exact same pitch space, however, the tenor and contratenor are not
equivalent parts. Each of them behaves, so to speak, according to its station within the textural hierarchy.
It is the tenor and only the tenor that makes the true discant cadence against the cantus, moving out from
sixth to octave, whether on the final (mm. 3–4, 23–24, 34–35) or on some subsidiary degree (D in mm. 8–
9 and 13–14, E in m. 32–33, the “open” cadence of the middle section). At such moments the behavior of
the contratenor is also mandated: it invariably fills in the middle of the double leading-tone cadence. That
is what defines it as a contratenor. A contratenor (or a tenor, or a cantus) is as a contratenor (or a tenor, or
a cantus) does.
Thus, even if Machaut wrote all the parts in one sitting, and there is no reason to suppose that he did
not, he nevertheless provided three grammatically viable or correct performance possibilities. Writing in
this way—so that the cantus can be sung either alone, or in a duet with the tenor, or in a trio with tenor and
contratenor—is often called “successive composition.” We imagine the composer writing the cantus first,
then adding the tenor, and finally the contratenor. We have already seen lots of evidence that this was often
enough the actual procedure. But it does not follow that the composer had to write the parts separately, or
that he could not conceive of a three part texture in a single act of composing.
Interpreting the idea of “successive composition” too literally can lead us into making unwarranted
and probably fallacious assumptions about the way in which people “heard” music in those days—for
example, that they did not “hear” harmony the way we “hear” it, but only an interplay of contrapuntal
voices that just happens now and then to produce (as if by accident) what we call “chords.” (The quotes
around “hear,” of course, are there to show that what is meant is not just hearing but conceptualizing on
the basis of hearing.) What we call “successive composition,” then, is merely the process of assigning
strictly defined roles to the various parts in a contrapuntal texture. The reason for it does not seem to have
much to do with how one “heard,” but rather with the fluid and practical attitude that demanded not a
single idealized text but a variety of performance possibilities for any song.
And that is why, even if he conceived all the parts in a song like Tres bonne et belle as a single
harmonic unit, Machaut needed to differentiate the tenor and the contratenor in terms of function, if not
style. For them to alternate roles on successive cadences, for example, would preclude a two-part
performance of the piece, for in that case not all of the cadences would be properly enunciated no matter
which of the two accompanying parts were used. And yet the fact that the tenor and contratenor had to be
functionally distinct seems to have led to their being stylistically distinct as well. The contratenor, being
in quasi-architectural terms the least “structural” voice (in that the other two voices could perform the