Medieval authorship is a fragile concept, yet digital approaches offer a path towards clarity. This book examines the work of Jehan de Saint-Quentin, an under-studied author from fourteenth-century France who has been credited with twenty-four poems, but whose name only appears in one of them. This volume expands Jehan's oeuvre through the addition of two new poems, namely Le dit de Guillaume d'Engleterre and Le dit de Robert le Deable. It also identifies echoes of two lost works by the same author in La vie saint Jehan Paulus and Richard sans Peur. Through this case study, the book offers a new model for the field, demonstrating how humanistic approaches and reproducible data can combine in bespoke ways to unlock new insights about medieval literature.