This article explores the role attributed to disturbed emotions in the understanding of old-age mental incapacity in eighteenth-century Tuscany. It claims that interdiction procedures provided a fertile forum for the negotiation of what constituted mental incapacity in old age, which progressively involved a discussion on accepted or proper emotional reactions. Delving into the language employed in interdiction narratives, it argues that references to disturbed emotional states were increasingly employed as a means of providing evidence of disordered states of mind. It also suggests that the constituent elements of mental incapacity and the emotional reactions deemed indicative of its presence were dependent on the familial and sociocultural context in which the behavior was identified. Interdictions thus reveal the articulation of a collective, culturally embedded language of mental incapacity that was profoundly entrenched in the formulation of behavioral norms and the shaping of standards of emotional reaction.