Tonal Organisation in Some F-MS Two-Voice Motets

The essay examines the tonal organisation of two-voice motets from Firenze, Biblioteca Medicea Laurenziana, ms. Pluteo 29.1. For each of them, the way in which the Tenor was extracted from chant, the melodic pattern of the upper voice, and the vertical relationships that subdivide the music continuum into discrete units are taken into account. The analysis reveals that (1) octoechos modality is a very weak structuring element of the musical flow, despite the modal-by-definition nature of their Tenores, and therefore (2) motet tonal organisation is not regulated by modal considerations, but by the force of the vertical interaction of the two voices. The comparison with conducti from the same Gothic repertoire that closes the essay, finally, shows that, paradoxically, the modal texture is weaker in motets than in conducti, even though these one have no connection to pre-existing liturgical melodies.