Marchetto published two major treatises, the (probably in 1317–1318), and the (probably 1318). He also published an abridged version of the as the , though the date of this is not known. He stated in the that he wrote it while staying at the house of
Raynaldus de Cintis in
Cesena, who was lord of the city from 1321 to 1326, however most scholars believe that the was written in 1318. The meanings of the two titles are: , an encyclopaedic clarification and
pomerium, which originally meant the boundaries of the city of Rome but by Marchetto's time had taken on the meaning of an enclosed orchard or green space. Precise dating of his work has been important to
musicology because of the controversy over whether he was influenced by the innovations of the French
ars nova, as written by
Philippe de Vitry and
Jean de Muris in the 1320s, or whether the influence went the other way. Most likely Marchetto's work was first, although he was well aware of the French practice – which, like most innovations in music before the 20th century, was only discussed in writing years after the actual musical innovation took place. All of the treatises except for the abridged version are in a heavily
scholastic framework, and were almost certainly collections of oral teachings. Marchetto's innovations are in three areas: tuning, chromaticism, and notation of time-values. He was the first medieval writer to propose dividing the whole tone into more than two parts. A
semitone could consist of one, two, three, or four of these parts, depending on whether it was, respectively, a
diesis, an
enharmonic semitone, a
diatonic semitone, or a
chromatic semitone. Marchetto preferred to widen major intervals and narrow minor ones for melodic effect, the opposite of what the later
meantone temperament does. The exact size of the major sixth he described is the subject of some disagreement, but was considered by
George Secor to be
12:7 (933 cents). In the area of time values, Marchetto improved on the old
Franconian system of notation;
music notation was by this time evolving into the method known today where an individual symbol represented a specific time-value, and Marchetto contributed to this trend by developing a method of compound time division, and by assigning specific note shapes to specific time values. Additionally, Marchetto discussed the
rhythmic modes, an old rhythmic notation method from the 13th-century
ars antiqua, and added four "imperfect" modes to the existing five "perfect" modes, thus allowing for the contemporary Italian practice of mixed, flexible and expressive rhythmic performance. The also included one of the earliest texts addressing the relationship between
composer – Marchetto used the word
musician, borrowing from
Boethius's definition in – and
performer. He set a distinct hierarchy, defining the "musician" or composer as the artist making judgements in accordance with his learned knowledge, while describing the singer as the instrument on which the musician performs, and likening their relationship to that of the judge and the crier. Marchetto's treatises were hugely influential in the 14th and early 15th centuries, and were widely copied and disseminated. The
Rossi Codex, which is the earliest surviving source of secular Italian polyphony and which contains music written between 1325 and 1355, shows obvious influence of Marchetto, especially in its use of his notational improvements. Without the innovations of Marchetto, the
music of the Italian Trecento – for example the secular music of
Landini – would not have been possible. ==See also==