The evidence for Greco-Roman astrology deserves to be considered separately from that for astronomy. Our primary source of information is again transmitted astrological texts, and these include books with named authors, among them Ptolemy. But in the surviving literature of this field Ptolemy is a comparatively early author. Our only transmitted astrological works composed before Ptolemy’s Tetrabiblos are Manilius’ Astronomica (early first century ce), a Latin didactic poem popularizing the science for a general readership, and the poem of Dorotheus of Sidon (mid-first century ce), meant for practitioners, which we have only in an Arabic translation of a lost Pahlavī translation. Other treatises with identified authors from after Ptolemy include those of Vettius Valens (late second century ce), Firmicus Maternus (first half of the fourth century ce, in Latin), and Hephaestion of Thebes (ca. 400 ce). Besides such more or less coherent works, however, the Byzantine manuscript tradition presents us with a vast quantity of anonymous astrological texts and texts that bear dubious or pseudepigraphic attributions, for the most part difficult to date or trace to original sources, and hence constituting a great challenge to the historian of the subject. The majority of this indiscriminate material is still either unpublished or available in unsatisfactory editions such as those in the appendices of the Catalogus Codicum Astrologorum Graecorum (1898–1953).
Many papyri and ostraca from the first century bce on contain astrological texts. Much of this material is similar in character to the transmitted astrological literature, consisting of didactic and reference texts. They are an underutilized resource, and numerous identified fragments still lack even an edition. This is even truer of the many astrological papyri in demotic Egyptian, which have the potential to illuminate the role of Egypt in the formation of Greek astrology as well as later relations between the two linguistic groups in Egypt.
Personal horoscopes constitute a special and important category of astrological papyri and ostraca. Unlike the horoscopes intermittently embedded in the transmitted literature, which were chosen if not actually fabricated to illustrate particular theoretical or methodological points, these are the unmediated horoscope documents pertaining to real people, and thus they inform us in various ways about the chronological and social patterns of astrology’s popularity in Egypt. A small number of archaeologically recovered horoscopic documents are also known from outside Egypt in the form of graffiti, inscriptions, and inscribed gems and jewellery. One example of a public astrological inscription exists, the so-called horoscope frieze of Antiochus I of Commagene (first century bce) at Nemrud Dag, a royal monument displaying visually what must have been understood to be an astrologically significant configuration of the heavenly bodies, though it is not a complete horoscope. Other inscribed objects relating to astrology include zodiac boards used by astrologers to display astrological configurations to their clients and peg-board inscriptions that allowed one to track significant time cycles including the astrological sevenday week.
Lastly, images relating to astronomy and astrology in ancient visual art are witnesses to the extent to which these sciences were in the public eye, and also sometimes to religious or political appropriation of this imagery. The most common entities to be portrayed were celestial spheres, provided with the principal circles in spherical astronomy, such as the equator, tropics, and ecliptic, or with constellation figures, or with both; sundials; zodiacs; and figures of individual constellations, especially those of the zodiac.
Jones, A., 2018, "Greco-Roman Astronomy and Astrology" in The Cambrdige History of Science, vol. I: Ancient Science, ed. A. Jones & L. Taub, 374-401. Cambridge: Cambridge University Press.
