Johannes de Garlandia (music theorist)

Johannes de Garlandia (Johannes Gallicus) (fl. c. 1270 – 1320) was a French music theorist of the late ars antiqua period of medieval music. He is known for his work on the first treatise to explore the practice of musical notation of rhythm, De mensurabili musica; prior to this time, music notation applied to pitch only.

Until the mid-1980s it was believed that Johannes de Garlandia lived in the first half of the 13th century and wrote two treatises, De Mensurabili Musica and De plana musica, and thus was intimately connected with the composers of the Notre Dame school, at least one of whom — Pérotin — may still have been alive in the earlier part of his career. Unfortunately the linking of his name with those two works only began after 1270, and it now seems likely that Garlandia was one Jehan de Garlandia, a keeper of a bookshop in Paris, records of whom appear on various official Parisian documents between 1296 and 1319. Most likely he was an editor of the two previous anonymous treatises, and while he did much to clarify them and transmit to them to posterity, he did not write them.

Sources writing about Garlandia in the late 13th and early 14th century also call him a magister, indicating he probably had a role as a teacher at the University of Paris.

De mensurabili musica, most likely written around 1240, is the single most important treatise in the early history of rhythmic notation, for it is the first to propose notation of rhythm. Specifically, it describes a practice already in use, known as modal rhythm, which used the rhythmic modes. In this system, notes on the page are assigned to groups of long and short values based on their context. De mensurabili musica describes six rhythmic modes, corresponding to poetic feet: long-short (trochee), short-long (iamb), long-short-short (dactyl), short-short-long (anapest), long-long (spondee), and short-short (pyrrhic). Notation had not yet evolved to the point where the appearance of each note gave its duration; that had still to be understood from the position of a note in a phrase, which of the six rhythmic modes was being employed, and a number of other factors.

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