This dissertation is a study of four poetry sources—three manuscripts and one early print—and their relationship to the fifteenth-century French secular polyphonic chanson. Three of the poetic sources are true anthologies, and all were compiled from smaller, internally consistent collections of poems, many of which poems survive with musical settings in notated sources of the period. This suggests that at least some of the exemplars from which this poetry was copied were themselves notated. The first chapter examines Berlin, Staatliche Museen Preußischer Kulturbesitz, Kupferstichkabinett MS 78.B.17 (the Rohan Chansonnier), and identifies collections from Paris and central France, as well as collections featuring poetry by Alain Chartier and members of the French royal court. Chapter 2 investigates Paris, Bibliothèque Nationale, MS fonds français 1719, and determines that at least two, and possibly three of its constituent collections were copied from musical exemplars, including one from the French royal court of the 1470s and 80s. Chapter 3 studies Antoine Vérard’s ground-breaking print Le Jardin de plaisance et fleur de rethoricque, an extremely important repository of many fifteenth-century chanson texts. These texts, in nineteen collections, were organized according to a carefully conceived strategy, probably by a former employee of Charles d’Orléans, the poet Regnauld Le Queux. It is possible to identify musical collections within the volume emanating from the courts of the Burgundian duke Philippe le Bon, and Jean de Bourbon at Moulins. Chapter 4 discusses British Library MS Lansdowne 380. This volume was written for a young, unmarried girl to serve as an instrument of her education. This was likely Elizabeth Kingston, who married William Kingston, counsellor and body man to King Henry VIII of England. The chanson texts preserved within the volume appear to reflect repertory cultivated at the court of either Antoine or Jean Croy, vassals to Philippe le Bon, and offer concrete evidence of English interest in the French polyphonic chanson of the fifteenth century. These four poetry sources also provide information about specific compositions, allowing us to re-date specific chansons by Hayne van Ghizeghem, Loyset Compère and Alexander Agricola.