The Medieval Poetics of Contraries explores the way in which medieval vernacular literary authority was produced at the intersection of the sacred and secular. Through close analyses of the texts and their manuscript reception, Bolduc unveils how religious authors establish themselves as vernacular lyric poets and, conversely, how writers of fictive works sanctify their poetic voices. Focusing on such authors as Gautier de Coinci, Matfre Ermengaud, the Fauvel authors, and Dante, Bolduc presents four models for manipulating contraries. Moreover, she engages multiple theoretical perspectives--medieval and modern--to suggest that contraries and literary authority were in the Middle Ages deeply dynamic, changeable, and profoundly poetic notions. Unlike previous works examining a single philosophical paradigm, generic framework, or national literature, this study rereads the relation of medieval contraries and authorship, exploring texts of highly indeterminate genre, which are simultaneously religious and courtly. In addition, this study engages wide-ranging national literatures from the early thirteenth to the early fourteenth centuries and from works in Old French to works in Occitan and Italian. The Medieval Poetics of Contraries considers contraries and literary authority within a broad philosophical framework, medieval as well as modern. It thus realigns current discussions of contraries, exploring them as important features of the construction and reception of vernacular literary authority.