The texture might be compared with a finely wrought tapestry: a weave of melodic strands that are
given a high profile at their beginnings, receding from there into the harmonic warp and woof. What
brings the river metaphor to mind, with its suggestion of placid, time-forgetful flow, are the harmonic and
rhythmic dimensions. The harmonic or tonal plan is extremely stable. Its stability is achieved by a strong
emphasis on what might be called the “structural pitches,” so defined on the basis of their function within
the built-in structure of the mode, in this case what Glareanus had dubbed “Ionian,” with C as final.
Every entry of the first phrase (“in illo tempore”) is either on the final or on the tuba or reciting tone
(to recall some Frankish terminology from long ago), namely G. Entries on the final proceed by a rising
fifth to the tuba, describing the modal pentachord. Entries on the tuba proceed not in literal but in