Generally acclaimed the greatest composer of the 14th century is Guillaume de Machaut. Like so many other medieval composers, Machaut was both musician and poet. His works are preserved to a degree astonishing for the 14th century: there are manuscripts for hundreds of poems and some 145 musical works. The poems are particularly fascinating for the light they shed on Machaut's own life and times; they record such events as the Black Death, which ravaged Europe in 1348 and 1349, and the Siege of Rheims in the early part of the Hundred Years' War. On a happier level his poetry reveals a love of falconry, riding, and the beauties of the French countryside. In some respects a conservative who built on existing traditions, such as the isorhythmic motet and even the monophonic trouvère song, he was, however, a composer of rare versatility whose music covers a range much wider than that suggested by his most famous work, the Messe de Nostre Dame (Notre Dame Mass). He was born in Champagne around 1300. In the early 1320s he entered the service of John, Duke of Luxembourg and King of Bohemia, who secured for Machaut various ecclesiastical posts, documented in a series of papal bulls. One of the most important was a canonry at Rheims Cathedral, although there is no evidence that Machaut was ever a practicing clergyman or even particularly pious; indeed, most of his music is secular. He remained in John's service until the latter's death at the Battle of Crécy in 1346, after which his continuing association with high nobility enabled him to travel freely. Around 1350 Machaut found a new patron in Charles, King of Navarre and pretender to the French throne. The fame of the Messe de Nostre Dame has tended to obscure Machaut's secular works; his songs are his most characteristic pieces. Lyrical in spirit, with a new emphasis on melody in the top or cantus line, they nevertheless contain considerable subtleties in their manipulation of musical and verbal refrains. One of the most popular of the so-called formes fixes of the day was the virelai, a principal feature of which is that words and music have refrains that do not coincide with each other. Most of Machaut's virelais are monophonic, showing the continuing influence of the trouvères. These represent the most approachable side of his art, particularly in as happy an example as the delightful Foy Porter. Two other song forms Machaut cultivated were the rondeau and the ballade. A particularly striking example of the latter is Dame, de qui toute ma joie vieni, a song of infectious rhythmic vitality in praise of the poet's lady. Set polyphonically for four voices, this ballade, like the virelai mentioned above, has three strophic stanzas. The musical form of this and other ballades is A-A-B-C, the last section being a verse refrain. The celebrity of the Messe de Nostre Dame probably owes much to its place in musical history as the first extant complete mass setting by a single composer. It is however possible that (as with Bach's Mass in B minor) its individual sections were not composed with a view to complete performance, a supposition supported by the work's diversity of styles and absence of thematic unity. Complex isorhythms are applied to all four parts in the shorter-texted sections (Kyrie, Sanctus, and Agnus Dei), while the Gloria and the Credo are monosyllabic. The title, incidentally, refers not to Notre Dame in Paris, but the great cathedral of Rheims, the coronation place of the kings of France and, as already mentioned, the location of Machaut's canonry.