This article combines a study of Peter Martyr Vermigli’s Sacred Prayers with a methodological concern for the particular challenges involved in coming to grips with prayers as historical sources. It demonstrates that in the reception history of Vermigli’s prayers there has been a recurring tendency to read them as something other than prayers, a commentary on the Psalms for instance. By contrast, this article attends to the specificity of their genre and form as prayers. This approach leads, first, to a fresh appreciation of the Preces sacrae as a rare and revealing source of their kind, since not many prayers offered before lectures in sixteenth-century Protestant universities have survived; secondly, to the discovery of important, as yet unknown connections between Vermigli’s Preces sacrae and Wolfgang Capito’s Precationes; and thirdly to an understanding of the spiritual depth of the Preces sacrae going beyond their propositional theological content.