Guillaume de Machaut (French: [ɡijom də maʃo]; also Machau and Machault; c. 1300 – April 1377) 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 what is now termed ars subtilior. Regarded as the most significant French composer and poet of the 14th century, he is often seen as the century's leading European composer.