Philippe de Commynes, a diplomat who specialized in clandestine operations, served King Louis XI during his campaign to undermine aristocratic resistance and consolidate the sovereignty of the French throne. He is credited with inventing the political memoir, but his reminiscence has also been described as ‘the confessions of a traitor’: Commynes had abandoned Louis’ rival, the Burgundian duke Charles the Bold, before joining forces with the king. This study provides a literary re-evaluation of Commynes’ text – a perennial subject of scandal and fascination – while questioning what the terms ‘traitor’ or ‘betrayed’ meant in the context of fifteenth-century France. Drawing on diplomatic letters and court transcripts, Irit Kleiman examines the mutual connections between writing and betrayal in Commynes’ representation of Louis’ reign, the relationship between the author and the king, and the emergence of the memoir as an autobiographical genre. This study significantly deepens our understanding of how historical narrative and diplomatic activities are intertwined in the work of this iconic, iconoclastic figure.