Carol Williams is an adjunct research fellow with the Centre for Medieval and Renaissance Studies at Monash University has an established academic career in both musicology and history. She is one of the collaborating editors and translators of the Ars Musice of Johannes de Grocheio (Medieval Institute Publications, 2011) and the Tractatus de tonis of Guy of Saint-Denis (Medieval Institute Publications, 2017). Her other publications include the essays ‘Modes and Manipulation: Music, the State, and Emotion’ and ‘The Tonary as Analytic Guidebook for the Performance of Chant’. She is also a performing musician, singing and playing in the early music ensemble, Acord. This paper – ‘Affects and Passions of the Soul: Aristotelian Influence in Music Theory’ – was delivered at ‘Emotions of Cultures/Cultures of Emotions: Comparative Perspectives’, the inaugural conference of the Society for the History of Emotions in December 2017.