Catherine of Siena (1347-1380) wrote almost four hundred epistles in her lifetime, effectively insinuating herself into the literary, political, and theological debates of her day. At the same time, as the daughter of a Sienese dyer, Catherine had no formal education, and her accomplishments were considered miracles rather than the work of her own hand. As a result, she has been largely excluded from accounts of the development of European humanism...