The Chansonnier Cordiforme (1470s) or Chansonnier de Jean de Montchenu is a cordiform (heart-shaped) music manuscript. Manuscript on parchment. Opens into a butterfly composed of the hearts of the two lovers who send love messages to one another in each one of the songs. The songs in French and Italian, written for different voices, are the work of some of the finest medieval composers. When the word “heart” appears in the texts, it is represented by a delicate pictogram.
Un superbe chansonnier en forme de coeur lui aussi celui de Jean de Montchenu, d’un siècle postérieur à Machaut via http://www.vlamarlere.com/article-23125679.html Guillaume de Machaut(c. 1300 – April 1377), was a Medieval French poet and composer.
Gregorian chant is, of course, vocal music. The text, the phrases, words and eventually the syllables, can be sung in various ways. The most straightforward is recitation on the same tone, which is called syllabic as each syllable is sung to a single tone. Likewise, simple chants are often syllabic throughout with only a few instances where two or more notes are sung on one syllable.