FIG. 6-4 Opening of Viderunt omnes, set as organum quadruplum by Perotinus for performance in 1198 (Flo, fols. 1–2).
In context, of course, the chord is heard as implying its resolution to the normative consonance. Note
that in making the resolution, every voice proceeds by step. The dissonant second between the triplum and
quadruplum arises not out of some “nonharmonic” medieval way of hearing (as we are sometimes
tempted to imagine it), but out of the implied voice-leading rule that dissonance proceeds to consonance
by step. We have, in short, the beginnings of a cadential practice here, in which the motions of the
individual parts are subordinated to an overall harmonic function (maximum dissonance resolving to
maximum consonance). This is the beginning of harmonic tonality (or, if you prefer, of tonal harmony). It
exemplifies textural integration, control, and planning.
EX. 6-4 Viderunt omnes a 4 (attributed to Perotin), first syllable of setting