placement puts the superius and tenor—the “structural pair” as they were regarded by composers and
theorists—on one side of the opening, and the two compositionally “nonessential” contratenors, the altus
and the bassus, on the other.
In Fig. 12-4 the positions of the bassus and the tenor seem to have been switched. In fact only their
names have been transposed, in deference to the newer meaning of the term “tenor,” then just coming into
use, which designated a range rather than a function. And here we come to the nub of the distinction,
drawn but not defined above, between an imitation and an emulation.
An imitation is simply a reproduction, a copy, a match—or, as often remarked, a compliment. An
emulation is both an homage and an attempt to surpass. The dynasties of composers and of compositions
that so distinguished the fifteenth and sixteenth centuries were dynasties of emulation. Works of “high”
style became models for other works that aspired to highness in a spirit at once of submission to a
tradition and mastery of it, and in a spirit at once of honoring and vying with one’s elders. A composition
regarded as especially masterly will come to possess auctoritas—authority. It sets a standard of
excellence, but at the same time it becomes the thing to beat. A true emulation will honor the model by
conforming to it, but it will also distinguish itself from the model in some conspicuously clever way.
The original Caput Mass set such a standard and inspired such emulation, and Ockeghem’s way of
distinguishing himself was to transpose the tenor down an octave so that it became the effective bass—no
doubt originally sung by the composer himself, leading his choir not only with claps on the back but with
his famously deep voice. That is what the little rubric says next to the “bass-playing-tenor” (in Latin,
bassus tenorizans) in Fig. 12-4: Alterum caput descendendo tenorem per diapason et sic per totam
missam, “Another head [appears] by lowering the tenor an octave, and thus for the entire Mass.” It will
not be missed that the “head” (caput) has now become the “foot” of the texture. That sort of playful
cleverness was part of the emulation game; and yet (as is emphatically the case here) that playfulness, at
its best, gave rise to music of high seriousness and eloquence.
Any practicing fifteenth-century musician would have been impressed with Ockeghem’s sheer
audacity in transposing this particular cantus firmus melody down an octave, to the foot of the texture. For
it begins with the one note—B natural—that normally cannot function as a bass, since the diatonic pitch
set can offer no perfect fifth above it with which it can resonate. To put it in more modern, avowedly
somewhat anachronistic terms, it cannot function under normal conditions as a harmonic root. So
Ockeghem creates abnormal conditions.
He goes ahead and writes an F above the cantus firmus B anyway, which forces alteration of the F to
F#causa necessitatis (“by necessity”), producing what we would call a B-minor triad. But the F# is
immediately contradicted by the superius’s F-natural against the second cantus firmus note, D, producing
what we would call a D-minor triad. This harmonic succession, by virtue of a root progression by thirds
and a melodic cross relation, is still weird to the ear after half a millennium. Immediately reiterated and
confirmed in the Gloria, it becomes a kind of signature for this Mass.
Nor is F/F# the only “cross relation” to be found in the work’s harmonic texture. Within the first
subsection of the Kyrie there is an equally teasing interplay of B-natural and B-flat (occasionally called
for by specific notational sign). By harnessing the old devices of music ficta to new and especially
pungent effect—an effect implicit in the cantus firmus that he has taken over from an earlier composer, but
one that the earlier composer had not exploited—Ockeghem announces his emulatory designs on the
Caput tradition and proclaims himself a worthy heir to his distinguished predecessor.
Who might this distinguished predecessor have been? Why should an anonymous English Mass have
attracted such determined emulation? The likelihood, of course, is that in Ockeghem’s day the Mass was
not anonymous. Ockeghem probably knew for a fact something about which we now can only hazard
guesses. The gargoylish manuscript illuminations in Fig. 12-4 (p. 458) give a fascinatingly oblique hint as