The Single Tradition Hypothesis: The Magical Gems of Antiquity and the Science of Images

The engraved "magical gems" of the Roman Empire, some four thousand intaglios of the first to fourth centuries now catalogued by classicists, and the Science of Images (scientia imaginum), the art of the astrological talisman transmitted by the Arabic Ghāyat al-ḥakīm, the Latin Picatrix, the Hermetic lapidaries, and Agrippa, have been studied as two subjects by two disciplines that do not cite each other. This paper argues that they are one tradition. A small but distinct class of the gems reproduces the images that the medieval books prescribe, in several cases the very images the Picatrix attributes to Hermes and the old sages. The gems of that class are cut, in a large majority of cases, in the stones the books assign to the same planets; some of them declare an astrological state, a planet in its own sign, that has no devotional motive; and they carry the inscriptions and stated purposes by which specialists define a working amulet. A Greek manual of the same period, the Sacred Book of Hermes to Asclepius, prescribes the books' recipe form, image, stone, plant, and ring, with only a single timing rule, and the medieval lapidary of Thetel, as Leonardi transmits it, describes the commonest magical-gem type, the armed figure with the head of a cock or a lion and vipers for feet on jasper, as a prescription, figure, stone, and purpose with no heaven named, which is the form the hypothesis predicts for the craft's oldest layer; Leonardi owned one, and reads its figure by the virtues of its stone. The complex election that defines the medieval art is therefore its latest layer, added between the end of gem production in the fourth and fifth centuries and the earliest Arabic image texts of the ninth, most likely in the seventh or eighth century under Persian astrology; the earliest datable text of that elected stream, Thābit ibn Qurra's De imaginibus, prescribes cast metal figures and names no stone, and the Ghāyat al-ḥakīm is the first book in which the two streams are joined. The Science of Images is a branch of lapidary lore that acquired astrology, not a branch of electional astrology that acquired stones. The paper states the hypothesis, presents five exhibits, specifies the four tests, and names the observations that would refute it. This précis states the hypothesis, the four tests, five exhibits, and the observations that would refute it, and is deposited to place the claim and its date on record ahead of the full study (catalog, counts, and the argument from the texts), which is in preparation. The file is under restricted access until that study appears; the abstract and metadata are public. Requests for access may be sent through the request button and will be answered at the author's discretion.