This thesis investigates conceptual networks —systems of organising, understanding and explaining thought and knowledge— and the ways in which they underlie both text and its mise en page across a range of thirteenth- and fourteenth-century French and Catalan literary texts and their manuscript witnesses. Each of the three chapters explores a separate corpus of texts, using two of four interrelated network theories: Michel Serres’ notion of parasites and hosts as the basic interconnecting units that combine to constitute all relational networks; the ubiquitous organizational tree; Gilles Deleuze’s concept of the fold as the primary factor in producing differentiation and identity; and Gilles Deleuze and Félix Guattari’s unruly, anti-hierarchical and anti-arborescent rhizomatic systems. The first chapter engages primarily with parasites and trees; the second with trees and folds; and the third with folds and rhizomes. However, resonances with the other network theories are discussed as they occur, in order to demonstrate the fundamentally interconnected and often interchangeable nature of these systems. Each chapter includes close analysis of manuscript witnesses of the texts under discussion. The first chapter, ‘Saints Denis and Fanuel: Parasitism and Arborescence on the Manuscript Page’, examines parasitic and arboreal networks in two hagiographic texts: late thirteenth- and early fourteenth-century prose redactions of the Vie de Saint Denis, and the thirteenth‐century hagiographic romance Li Romanz de Saint Fanuel. The second chapter, ‘Ramon Llull’s Folding Forests: The World, the Tree and the Book’, addresses arborescent and folding structures in Llull’s encyclopaedic Arbre de ciència [Tree of Science], composed between 1295 and 1296. The third chapter, ‘Transgender Genealogy: Turning, Folding and Crossing Gender’, considers three characters in medieval French texts who can be read as transgender: Saint Fanuel; the King of Torelore in Aucassin et Nicolette; and Blanchandin/e in Tristan de Nanteuil. The chapter explores the ways in which these characters’ queer trajectories can be understood through conceptions of directionality which relate to the fold and the rhizome.

La Chronique universelle de la Création jusqu'à Constantin, demeurée à ce jour inédite dans sa version occitane complète, voit probablement le jour en terre catalane au tout début du quatorzième siècle, avant d'être traduite en occitan et en italien. Copié aux confins du Languedoc et de la Provence, le manuscrit D présente une langue influencée par le catalan et teintée de français. Quant au manuscrit G, copié en Béarn et bien connu sous le nom de Récits d'Histoire Sainte en Béarnais depuis son édition par Lespy et Raymond, en plus de conserver le seul texte littéraire béarnais de cette époque, il a connu une longévité exceptionnelle puisqu'il fut en usage jusqu'au dix-huitième siècle. / The Chronique universelle de la Création jusqu’à Constantin, which has remained unpublished to this day in its complete Occitan version, probably appeared in Catalonia at the beginning of the fourteenth century, before being translated into Occitan and Italian. Copied on the borders of Languedoc and Provence, Manuscript D contains language that has been influenced by Catalan tinged with French. As for Manuscript G, which was copied in Bearn and has been well knownunder the name of Récits d’Histoire Sainte en Béarnais since it was published by Lespy and Raymond, in addition to preserving the only Bearnese literary text from this period, it is exceptional for the length of time that it was used, that is, up until the eighteenth century.