A Companion to Hildegard of Bingen

hearing the heavenly symphony 183
The musical structure of O vos angeli clearly echoes contemporary music
theory in Hildegard’s region, calling into question her disavowals of musical
knowledge. However, such a song could also come into being through
improvisation. In fact, the rigorous structure of the song provides exactly
the same type of fijixed points (the cadence notes and the melodic shapes
by which cadences are approached) that characterize much musical
improvisation. Moreover, regional modal theory was transmitted not only
in treatises, but also through songs that could be memorized and practiced
as vocal and pedagogical exercises.64 One of the most widespread
of these exercises (shown here in letter notation) teaches the basic principles
of South German theory and demonstrates them musically by fijilling
in the perfect consonances of diatessaron, diapente, and diapason, which
are named in its lyrics. While transmitted only in protus mode (on D, as
in Example 2), one need only sing it in deuterus (on E, as in Example 3)
to see how such exercises could provide the basic conceptual framework
behind Hildegard’s O vos angeli.
Example 2. Diapente et Diatessaron in Protus
(Paris, Bibliothèque nationale de France, Nouv. acq. lat. 1235, fol. 146v)65 , 66
66
64 Charles Atkinson wrote the seminal article demonstrating the ways in which the
ars musica and ars cantica converged: “The Other Modus: On the Theory and Practice of
Intervals in the Eleventh and Twelfth Centuries,” in The Study of Medieval Chant: Paths
and Bridges, East and West: In Honor of Kenneth Levy, ed. Peter Jefffrey (Cambridge, 2001),
pp. 233–56.
65 In this manuscript, the piece ends with the fijinal neuma from the fijirst mode formula
“Primum querite” omitted here. The song frequently appears in South German theory
compilations; see McCarthy, Music, Scholasticism and Reform, pp. 182–215.
66 “The diapente and diatessaron are concords (symphoniae), and rising and falling in
equal measure by the consonance of the diapason, they render consonant melody.”