Galen in the Late Antique, Byzantine and Syro-Arabic Alchemical Traditions

The main source that allows us to explore the origins of alchemy in the Graeco-Roman Egypt along with its late antique and Byzantine developments is a large collection of Greek alchemical writings (usually referred to as Greek alchemical corpus) that is handed down in various Byzantine manuscripts nowadays kept in important European libraries.1 Next to this collection, a few Greek papyri have been preserved in the hot and dry sand of Egypt; in particular, the so-called Leiden and Stockholm papyri (third–fourth century AD), sometimes defined as “(al)chemical handbooks”, collect hundreds of recipes describing metallurgical techniques, procedures for dyeing stones and wool, and methods for producing gold and silver inks.2 Different branches of medicine, such as pharmacology and surgery, are evoked in these alchemical texts. The four books on dyeing attributed to the philosopher Democritus (first century AD) urge the young practitioners, who want to prepare dyeing pharmaka, to follow the example of physicians, who carefully test the qualities of natural substances before mixing them in a healing drug.3 Indeed, eleven entries from Dioscorides’ On Materials for Medicine have been copied in the last two leaves of the Leiden papyrus (fols. 14-16), where they are introduced by the following title: “From Dioscorides’ On Materials (of Medicine)” (“Dioskoridou ek tou peri hylēs”). Each entry includes a short description of a mineral ingredient, thus providing alchemists with a helpful tool for identifying the natural substances and their properties. Not only issues of identification troubled ancient alchemists. They also tried to determine the exact quantities required in the different processes that were described in the texts they used to study and put into practice. In order to respond to such a practical need, Byzantine alchemical collections include a short metrological work attributed to the Egyptian

either of "Galenic" medicines or of alchemical drugs (2) to mix the right quantities of the required ingredients accordingly.
If we turn our attention to surgery, we must note that the Graeco-Egyptian alchemist Zosimos of Panopolis (third-fourth century AD) explicitly refers to illustrated books that explain how to mend fractures. Diseased patients -he says -were assisted by physicians "bearing books illustrated with geometrical drawings and hatched diagrams". 14 Regrettably, Zosimos does not specify the author(s) of similar handbooks. 15 Moreover, his text belongs to a rather difficult period in the history of medicine; after Galen's death, in fact, a variety of medical systems were competing with each other until the spread of Galenism (sixth-seventh century AD), when "arguments over the interpretation of Galen had replaced disputes over alternatives to Galen". 16 If different medical sources may be implied behind Zosimos' passage, 17 for later alchemical texts Galen's influence will become more evident.
The medical expertise of alchemists is emphasised again in the Byzantine alchemical poem On the Divine Art in Iambic Verses, falsely attributed to the philosopher Theophrastus (seventh-eighth century AD). 18 Its prologue praises the fortunate life of sophists (sophistai), i.e. learned men who, like rhetorical performers (rhētores), spent their days inspired by a great wisdom (pansophōs). Their education was not confined to alchemy, but touched upon a wide array of disciplines: natural philosophy, astronomy/astrology and medicine. A quite substantial section of the prologue is devoted to the last discipline: Yet, more than this, the causes we reveal Of each affliction in the body's frame;  If the parts had just one and the same treatment and they were by no means different one from another, there would be no parts at all. Indeed, each natural <or> artificial part brings something specific (ti xenon) into the whole (to holon; i.e. the whole entity to which the single part belongs), and without this part, the All (to pan) would remain incomplete, as is possible to see for the bodily parts, which Galen referred to as "places" (topoi); let's listen to his own words: the bodily parts -he says -are called "places" 26 . 27 In general terms, Christianos' line of reasoning seems to imply a certain analogy between the human body and the metallic body (called sōma in the alchemical writings). As each single bodily part contributes to form a complete human body, in the same way a metallic body represents the combination of different parts or components. By treating and combining these parts -we may suppose -the alchemist tried either to "synthesise" the perfect metallic body (namely, gold) or to produce specific substances that could bring about the metallic transmutation. 28 24 The chronology of this author is uncertain: Berthelot-Ruelle (1888: III.378-9) propose the sixth century AD; Letrouit (1995: 62) is more inclined to the seventh/eighth century AD. 25 These chapters are scattered in different sections of Berthelot-Ruelle's edition; for their correct order, see Letrouit (1995: 62). 26 28 According to Berthelot-Ruelle's interpretation (1888: III.262, n. 2), the expression "the All" (to pan) would have referred to the metallic alloy that was to be transformed into silver or gold. We must add that similar discussions about the simple or composite nature of natural or artificial substances are common in the Greek alchemical corpus: see, e.g., Viano (2015: 318-20) for an account of Zosimos' and Christianos' discussions on the nature of the so-called "water of sulphur" (or "divine water"), a central dyeing compound in ancient alchemy.
The argument developed by Christianos pertains to the philosophical question of the unicity of natural and artificial species, discussed for instance by the Neo-platonic philosopher and commentator Proclus (c. AD 410-85). In his commentary on the Republic, Proclus targets alchemists who "claim to make gold out of the mixture of certain species (ek mixeōs tinōn eidōn), while nature makes the one species of gold (to eidos hen tou chrysou) before the mixture of the species they talk about". 29 The alchemist Christianos adresses a similar philosophical issue by relying on the authority of Galen. Such a meaningful combination of philosophical and medical education points to a late antique scholar system. 30 After all, Galen's work On the Affected Parts was one of the sixteen treatises that belonged to the Alexandrian canon mentioned above.

Galen in the Syriac Alchemical Tradition
As already seen, the reference that Zosimos makes to surgical handbooks is too vague to understand whether he had specific medical authors in mind. On the contrary, the identification of the medical sources of some Syriac works attributed to Zosimos is certainly easier. A collection of twelve alchemical books has been preserved in Syriac under the name of the Graeco-Egyptian alchemist. 31 Alongside these books, which probably depend on (nowadays lost) Greek writings, we also find a somehow different and separated treatise that 1. The first Syriac section is a list of different minerals that depends on the part on metallika (i.e. mined substances) in Galen's book 9. 33 .
2. The second section describes different kinds of earth by following the order in which they are presented in Galen's book 9. 34 The part is introduced by the title: "Explanation of any kind of earth by the wise Zosimos".
3. The third section includes a list of stones that follows the order of the chapters devoted to the same topic in Galen's book 9. 35 A general statement opens the Syriac passage: " Now I deal with the stones that, if crushed with mortars and files, become liquid and produce a juice (chylos)". The following explicit closes the section: "End of the names of the stones that have healing properties of any kind and that are used by the wise physicians. Zosimos dealt with them and described them for the queen and priestess Theosebeia". 36 The medical framework from which the names of stones are taken seems to be acknowledged in the last explicit, despite of its attribution to the alchemist Zosimos rather than to the physician (and legitimate author) Galen. However, as we shall see, all the data regarding how physicians made use of these substances in healing practices are left aside.
Moreover, the original structure of Galen's book 9 is slightly distorted, since the Syriac abridgment opens with the description of the metallika, which rather constitutes the third and last part of Galen's book. The great relevance of this group of ingredients for the alchemical practice probably explains the opening position they occupy in the new alchemical pastiche of Galenic passages. The centrality of alchemical interests represented the main criterion that guided the selection of data to be kept in each entry. For instance, as far as diphryges (lit. "twice roasted") is concerned, we read: I took a lot of this medicine as well from a hill in the island of Cyprus. There was a mine from which (this substance) comes and that is thirty stadiums away from the city.
(This substance) lay in the region between a building that was close to the mine and 33 Galen, SMT, 9.3.2-40, ed. Kühn (1826) XII.210-44. 34 Galen, SMT, 9.1.1-4, ed. Kühn (1826) XII.165-92. 35 Galen, SMT, 9.2.2-21, ed. Kühn (1826) XII.195-208. 36 Theosebeia is a well-off (probably Roman) woman to whom Zosimos addressed many of his alchemical treatises. the city that was nearby the mine. The procurator who was in charge for that mine told us that (this substance) is what remains unused…from the heat of the furnaces". 37 When compared with the original Galenic passage on diphryges, 38 the Syriac passage is clearly shorter and leaves all the details about the medical properties and applications of the substance aside. In the new alchemical context, readers were probably more interested in useful information about the availability of the substances in different geographical areas or in a detailed account of their nomenclature.
Indeed, if we come to the fourth and last section of this Syriac section, just a dry list of names is taken from books 10-11 of Galen's pharmacological treatise. This section is simply introduced by the general incipit: "Explanation of further materia medica that belongs to the wise Zosimos". The first entries read as follows: gala, that is, milk.
boutyron, that is, oil of butter or butter or as you want to call it. pytia, that is, curdled milk.