In the late ninth or early tenth century CE, the Rayy-born Arabic-speaking physician Abū Bakr Muhammad ibn Zakarīyā al-Rāzī (865 – ca. 925 CE), better known in the medieval West as Rhazes and in contemporary scientific literature as Rāzī, wrote a treatise on Smallpox and Measles (Kitāb al-gudarī wa’l-hasbah), which represented the most advanced state of medicine at that time. In fifteen chapters, the work analyzes the causes of smallpox epidemics (chapter 1), the profile of the patients susceptible to succumb to epidemics (2), the circumstances under which epidemics start (3), the types of smallpox (4), the prevention (5) and therapy (6), particularly the treatment of eyes (7), and the general evolution of the disease (8). Then it returns to the therapy, which it treats exhaustively, including diet.

According to a still widely accepted historiography, Byzantium, which claimed to have inherited the legacy of Antiquity, and the West, which was emerging from a deep transformation of populations, society and political entities, had only at their disposal at Rāzī’s time poor medical manuals, deprived of theory.

Such a view might result from an insufficient inventory and analysis of the surviving manuscript evidence, the lack of a critical edition for many texts that are not necessarily of secondary importance, and probably also a classicizing tendency that a priori favours Antiquity and its early Byzantine continuity and simultaneously rejects its subsequent developments, indeed of a different nature.

As a proof of the richness of medical literature during the centuries preceding or immediately following Rāzī’s time one could mention, for the East, the recently edited manual of the less well-known Paul of Nicea, probably to be situated after the seventh century and before the ninth or tenth, and the medical encyclopedia of the tenth-century physician Theophanos Chrysobalantes mostly known under the name he was given in the Renaissance, Theophanes Nonnos. For the West, the so-called Lorscher Arzneibuch (or Medical Formulary of Lorsch) from the end of the eighth century and the St Gall Botanicus (Herbal) of the ninth century could be mentioned among many other examples.

If there is, indeed, an important medico-pharmaceutical literature of the early and, maybe also, of the late Middle Ages that has been ignored until recently and that should be explored more systematically, the question to be addressed is not so much why this body of knowledge has been neglected in contemporary medical historiography.