The fourth period of the old French school extended from 1230 to 1370. The three great names were Phillippe de Vitry, Jean de Muris and Guillaume de Machaut. They were regarded by their contemporaries as exponents of the _ars nova_, in contradistinction to the Franconian teaching, which was called _ars antiqua_. One of these differences was the use of a number of signs permitting singers to introduce chromatics in order to carry out the imitations without destroying the tonality. Jean de Muris was born in Normandy. He was a doctor in the Sorbonne, and from 1330 a deacon and a canon. He died in 1370. He was a learned man of an active mind. He speaks of three kinds of tempo--lively, moderate and slow. He says that Pierre sometimes set against a breve four, six, seven and even nine semibreves--a license followed to this day in the small notes of the _fioratura_. This kind of license on the part of the deschanteurs had been carried to a great length, the melodic figures resulting being called "_fleurettes_" ("little flowers"). John Cotton compared the singers improvising the _fleurettes_ of this kind to revelers, who, having at length reached home, cannot tell by what route they got there. Jean de Muris reproved them in turn, saying: "You throw tones by chance, like boys throwing stones, scarcely one in a hundred hitting the mark, and instead of giving pleasure you cause anger and ill-humor." Machaut was born in Rethel, a province in Champagne, in 1284. He was still living in 1369. He was a poet and musician who occupied important positions in the service of several princes, and wrote a mass for the coronation of Charles V. Naumann thinks that Machaut was the natural predecessor of the style of Lassus and Palestrina. He says that the use of double counterpoint slackened from this time, whereby the music of the Netherland composers--Dufay, Willaert and Palestrina--is simpler and less artificial than that of Odington and Jean de Garland. Chords were more regarded. This also had its source in the north. III.