‘Not in Accordance with Ptolemy in Some Details’: A Late Antique Revision of the Handy Tables

At the beginning of his treatise, "On the construction of an Aratean sphere", written in the mid-sixth century AD, the Alexandrian scholar Leontius Mechanicus addresses his dedicatee, the young apprentice Theodorus, with the following words: "For, as you know, all the spheres currently available are not in accordance with Ptolemy in some details, as is reasonable; but, with Aratus, they disa-gree in most of the information." This chapter shows how Leontius’s words can contribute to a more nuanced reconstruction of the late antique astronomers’s relationship to Ptolemy's authority, and of their role in the development of scientific knowledge between the end of antiquity and the beginning of the Middle Ages.