14 ). So well does it fit the pedagogical bill that scholars now suspect that Guido actually wrote the
melody himself on the familiar words of the hymn.
EX. 3-14 Hymn, Ut queant laxis; words by Paul the Deacon, music possibly by Guido d’ArezzoThis module gave a syllable-name (or vox, “voice”) to each degree (or locus, “place”) in the
hexachord. Once internalized, the set of “musical voices” (voces musicales) served a double purpose for
ear training. In the first place any interval, ascending or descending, could be demonstrated in terms of a
vox combination (thus: ut–re, the tone; ut–mi, the major third; ut–fa the perfect fourth; re–fa the minor
third; etc.). And, second, the difference between the tone and the semitone, the all-important definer of
mode quality, could be mastered by drilling the interval mi–fa.
Around the beginning of the seventeenth century, the syllable si, derived from the initials of “Sancte
Ioannes,” was added by some singing teachers to the Guidonian module so that a full major scale could be
sung with model (“solmization”) syllables. (In modern practice, as every music student knows, si has
been replaced by ti, and the closed syllable ut has been replaced by the open syllable do, sometimes
spelled “doh” in English speaking countries to avoid confusion with the verb “to do.”) Guido, however,
who did not as yet have or need the concept of the major scale, managed to complete the octave by
transposing the basic module so that it began on G, the hexachord G–E being intervallically identical (or
“affined,” to use Guido’s vocabulary) with C–A. In this new placement, the progression mi–fa
corresponds with the semitone B–C. To solmize the full scale from C to c, one “mutates” at some
convenient point (either on sol–ut or la–re) from one location of the module to the other, thus (dashes
denoting semitones):
To take care of the F-with-B-flat situation, later theorists recognized another transposition of the
module, beginning on F, that would place the mi–fa pair on A and B-flat. The whole range of hexachord
transpositions thus achieved, mapping out the whole musical space within which Gregorian chant was
habitually sung, finally looked like Ex. 3-15.
EX. 3-15 The gamut, or full range of pitches represented on the Guidonian hand, together with the seven hexachords that are
required for its solmization. The recurrent pitch names across the bottom of the diagram are called claves in medieval music
theory; the recurrent solmization syllables are the voces. An individual pitch, or locus (“place” within the gamut), is specified by
a combination of clavis and vox, from Gamma ut (whence “gamut”) to E la. What we now call “middle C” was C sol-fa-ut to
medieval singers