This thesis investigates medieval translation through the comparative studyofa group of Middle English Arthurian romances dating to the fourteenth and fifteenth centuries. Of Arthour and of Merlin, Henry Lovelich’s Merlin, and the English ProseMerlinderivedindependently from a common Old French source, the Vulgate Cycle’s Estoire de Merlin, and each author reshaped the material of the original presentingthe same story as their French sourcebut from very different and, at times, divergent perspective. The interventions by the three authors were heterogeneous and ranged from changes to the order of the narrative, through expansions andabbreviations, toomissions and additions.In an attempt to unveil the authors’ agenda, this thesis offers close textual analyses of these texts and investigates how the similarities and dissimilarities with their source and with each other reflect the social, historical, and literary contexts in which they were produced. The research builds on freshcriticalapproaches to medieval translation following the postcolonial turn intranslation studies, emphasising the role of the translator in the production of medieval texts and the function performed by translation in medieval England’s multilingual and multicultural context. It therefore seestranslation as a cultural,rather than a merely linguistic,phenomenonand as a practice that shaped English vernacular literature.Asthe datesof these textsspanover two centuries, this thesis explores the movementof the Merlin section of the Vulgate Arthurian legend as well as its shift from verse to prose in fourteenth-and fifteenth-century England, and before the composition of Thomas Malory’s Morte Darthur.