Ptolemy's Differentiation between Astronomy and Astrology in the Greek-Arabic-Latin Tradition.

This article examines Claudius Ptolemy's distinction between astronomy and astrology as presented in the first chapter of his *Tetrabiblos* (Apotelesmatika) and traces how this distinction was transmitted and transformed through Greek, Arabic, and Latin translations. Ptolemy differentiates astronomy as the demonstrable science of predicting celestial movements, while astrology studies the effects of these movements through less certain methods, yet he argues for astrology's philosophical legitimacy despite its epistemic limitations. Two main Arabic traditions of the *Tetrabiblos*—one associated with Ḥunayn ibn Isḥāq and another anonymous version—led to multiple Latin translations, each introducing nuanced expansions or reinterpretations, with the latter tradition notably elevating astrology's spiritual and philosophical status. These textual variations influenced medieval and Renaissance Western astrology, with translations by Plato of Tivoli and Egidius de Tebaldis being particularly influential, and the *Liber quatuor tractatuum* gaining prominence among scholars such as Roger Bacon.