Clement of Alexandria, in his work Stromata (Book VI, Chapter 4), described a procession of Egyptian priests, stating that 36 of the 42 "indispensable" books of Hermes, containing the entire philosophy of the Egyptians, were learned by various priestly orders. These included:
- Singer: Learned 2 books (hymns to gods, king's life).
- Horoscopus: Mastered 4 books on astronomy (fixed stars, planetary movements).
- Hierogrammat: Knew 10 books on hieroglyphics, cosmography, geography, astronomy, topography, sacred utensils, and temple matters.
- Stolistes: Studied books on animal slaughter and sacrificial rites.
- Prophet: Learned 10 "hieratic" books on laws, gods, and priestly training, also overseeing temple revenues.
The remaining 6 books, medical in nature (body structure, diseases, instruments, medicines, eyes, women), were studied by the Pastophoroi (image-bearers).