Guillaume de Machaut and his manuscripts have been the subject of much recent scholarship, with each investigation yielding new and often surprising information. This paper presents some of the results of my continuing study of the Machaut manuscript F-G (Paris, Bibliothèque Nationale de France, f. fr. 22545-6). I will trace aspects of its history from creation, illumination and damage, through original ownership, scandal and politics, to its 18th century ‘rediscovery’, evidence of early performance, and its role in shaping more general attitudes towards Machaut and his music. Each step of the way enriches our understanding of the circulation and meaning of Machaut materials, their relationship with the author and their use. Following the dramatic ups and downs in this source’s history teaches us not only about Machaut, but also about culture in general and ourselves as historian.