Among the most notable features of the religious revival in western Europe in the early thirteenth century was the development of mysticism among the nuns and religious women of the lowlands. As scholarly attention becomes increasingly focused on this group of remarkable women, the question arises whether a psychiatric viewpoint has something of value to offer to the understanding of such individuals and the culture in which they struggled. The methodological and intellectual problems inherent in examining the life of a thirteenth-century mystic with a twentieth-century empirical frame of reference are illustrated in this study of the adolescence of Beatrice of Nazareth. Beatrice's stormy asceticism, ecstatic states and mood swings lend themselves to potentially competing hypotheses regarding the spiritual and psychopathological significance of her adolescent development and eventual life-course. Common grounds for reconciling these alternative models are discussed.