next phrase of the original chant. That is what happens in Hucbald’s second, third, and fourth phrases, all
of which end on G. The second phrase is answered and “closed” by the full cadence on “Benedicimus te”;
the fourth by the close on “Glorificamus te.” The one in between (Qui dominator ...) is answered
strategically by “Adoramus te” with a cadence on D, so that a tonally closed ABA pattern sets off the
three parallel acclamations from the rest of the Gloria. This kind of tonally articulated formal structure
was the great Frankish innovation.
The same regular features can be discerned in many of the trope melodies discussed in chapter 2. That
is because the authors of tropes had to be music analysts as well as poets and composers. They had to
determine and reproduce the mode of the chant to which they were setting their prefaces and
interpolations, whether or not they actually intended to imitate the style of the earlier chant. (In practice, it
seems, some did so intend and some evidently preferred their new melodies to stand out from the old; all,
however, understood the requirement of modal conformity.) Consider the preface to the Easter Introit in
Ex. 2-8a. The mode of the Introit antiphon itself is given as the fourth (Deuterus plagalis or
Hypophrygian), and one can immediately see why: it begins with D, a note in the lower tetrachord (and
the first phrase, “Resurrexi,” actually cadences there); the range will later touch bottom on the C below
that. The highest note in the melody is A, which means that the full modal pentachord above E is never
expressed at all. Only the final cadence on E (something that could hardly be predicted at the outset)
justifies the assignment of the melody to the Phrygian tribe. The gap between the reality of the chant and
the utopia of mode theory yawns.
EX. 3-4 Gloria in mode 6, with laudes by Hucbald of St. Amand (texted in italics)