The French composer Guillaume de Machaut was the most prolific composer of his time, with surviving works encompassing many forms, the three formes fixes rondeaux, virelais, ballades, as well as motets, lais and a single representative of the complainte, chanson royale, double hocket and mass genres. Most of his extant output is secular music, a notable exception being the renowned Messe de Nostre Dame. His oeuvre as a whole represents an unprecedented volume of surviving music for a single medieval composer, largely in part due to his own efforts to preserve and curate manuscripts for his music. The dominant figure of the ars nova style in late medieval music, Machaut is regarded as the most significant French composer and poet of the 14th century and often seen as the century's leading European composer.
Since many titles are merely the first lines of the texts used, in different sources individual pieces may be referred to by slightly different titles. For example, R20 is known both as Douce dame and Douce dame tant qui vivray. Furthermore, some of Machaut's works (most notably the motets) employ simultaneous performance of several different texts. In such cases, the title of the work lists all texts used, starting from the top voice.
