Dated 1409 and dedicated to his patron Cardinal Branda of Piacenza, this treatise includes a discussion of modes and differentiae (Part 8) wherein Johannes de Olomons includes differentiae and intonation formulas for both Gregorian and Ambrosian chant. The differentiae are examined individually by mode, each with accompanying examples of antiphon incipits and the intonation formulas. There is some overlap between the Ambrosian and Gregorian differentiae and there appears to be no attempt to limit the diversity of differentiae patterns within each mode, with as many as 10 unique differentiae patterns per mode.
Johannes de Olomons, Palma choralis, ed. Albert Seay, Critical Texts, no. 6 (Colorado Springs: Colorado College Music Press, 1977).