Spiritual Diagrams and Cognition in the Writings of Guillaume de Deguileville

This article takes a new approach to the Pèlerinage allegories and later Latin poetry of the fourteenth-century Cistercian monk Guillaume de Deguileville. It argues that diagrams and “diagrammatic thinking” undergird his entire poetic oeuvre. The article situates Deguileville in a long medieval tradition of using diagrams as instruments for scientific and theological education. Deguileville understands diagrams not only as pedagogical tools, but as a way of structuring cognition and spiritual thought. Relying on ideas of similitude and analogy, these visual signs help his audience to process complex doctrines such as the Trinity. Deguileville’s diagrams operate as aids to spiritual contemplation, in some cases bypassing ordinary modes of perception to offer insight into the divine. Ultimately, Deguileville’s writings provide evidence of the rich complexity of medieval diagrams, which could function as cognitive prompts as well as deeply meditative and even sacramental images.