Guillaume de Machaut was a French composer and poet who was the central figure of the ars nova style in late medieval music. His dominance of the genre is such that modern musicologists use his death to separate the ars nova from the subsequent ars subtilior movement. Regarded as the most significant French composer and poet of the 14th century, he is often seen as the century's leading European composer. 1300 – 1377; died at about 77. Alive at the same time as Dante Alighieri, Marco Polo, William of Ockham, Giotto, and Bayezid I. Wiki link