Codex Parma De Rossi 997 (Palatina 1753, Richler 1098) is an extensive collection of private, occasional prayers copied in the Byzantine cultural orbit in the fifteenth century. Many of the supplications are philosophical in their content and terminology, and are ascribed to both Jewish and non-Jewish philosophers. Among the authors of these prayers one finds the names of Aristotle, Hippocrates and Maimonides. In my paper I propose to look at this genre of medieval literature, from different angles: transconfessional, philosophical, and literary. I will concentrate in particular on the prayers attributed to Aristotle. Supplications in his name are found in Arabic sources (for example, the anthology of Mubashshir bin Fātik), in Hebrew translations of the Arabic (e.g., Musarei ha-Filosofim), and eventually made their way to yeshivah students in sixteenth century Poland (see responsa 6-7 of R. Moses Isserles), where they were in part responsible, according to some historians, for the institution of Jewish censorship.