How and why did the story of St Katherine's passion, which did not generate a particularly exceptional devotion in Byzantium during the final centuries of the first millennium, end up transplanted to the fertile religious environment of eleventh-century Normandy? This study contends that Katherine's appeal to the Normans is rooted in her relative obscurity and verisimilar resemblances to early martyrs, and that the very early texts already contain the kind of information, theatricality, and disputes that made her so appealing in the Latin and vernacular West. This book examines the early textual tradition of St Katherine which remains relatively unstudied and unknown, taking as its starting point the moment at which Katherine's story becomes legible. Through codicological and textual analysis, it illuminates the origins and relationships of the various Greek and early Latin vitae, which continue to be misunderstood in the historiography of Katherine's cult, recalibrating our knowledge of the early textual tradition of one of the most venerated intercessors of medieval Western Christendom.