The Transmission of Planetary Theories in Ancient and Medieval Astronomy

Abstract

In Toledo in the year A.D. 1068 Abū’l-Qāsim Sā’id ibn Ahmad, also known as Qādi Sā’id, wrote a book entitled The Categories of Nations.¹ In this work he discusses the people of the world from the viewpoint of their interest in scientific research, stating that “the category of nations which have cultivated the sciences forms the élite and the essential part of the creations of Allah.”² Eight nations belong to this class: “the Hindus, the Persians, the Chaldeans, the Hebrews, the Greeks, the Romans, the Egyptians, and the Arabs.”³ Taking into account some terminological differences, this list can still be considered fairly complete. What Sā’id calls “the Romans” and “the Egyptians” in part coincides with what we would call the Byzantines and the Alexandrian School, while Rome and Egypt in our sense of these words could not compare in importance with India and the Hellenistic or Muslim contributions. But it is wise not to forget that the existence of the Roman Empire was an essential condition for the transmission of Hellenistic science to the Muslim world.