It grew to have an elaborate organization. It was abolished by Justinian in 529 A. D. =2. Alexandria.= There were many other centres of Hellenism and of other learning at this time,――Rhodes, Antioch, Alexandria, ♦Pergamos, Tarsus,――but none of these could be said to rival Athens in the veneration of men. Some were much more active and creative than Athens. Alexandria surpassed Athens and all other cities as the centre of the natural sciences in the Ethical Period and of religions in the Religious Period. Here, too, rather than at Athens, were to be found the real interpreters of Plato and Aristotle. Nothing in ancient times can be compared to the wonders of the museum of Alexandria, which was its university. Scholars of every nation were entertained here at the public expense. A vast botanical garden, a zoölogical collection, an anatomical museum, an astronomical observatory, a library of seven hundred thousand volumes were here. Here Euclid (290 B. C.) wrote his geometry, Eratosthenes pursued his astronomical, geographical, and historical labors, Apollonius wrote his treatise on conic sections; and here were made the observations that led to the discovery of the precession of the equinoxes. Here Ptolemy and his school formulated the system of astronomy which was authoritative for fifteen hundred years. Here the Christian theologians were educated, and from this city neo-Platonism sprang. Literature and art, history, philology and criticism flourished. The Hebrew Bible was translated into Greek. All religions were welcomed. Buddhist, Jew, Greek, and Egyptian mingled, and comparative theology rose to be a science. =General Characteristics of the Ethical Period= (322 B. C.–1 A. D.)――On the death of Aristotle the hitherto compact body of Greek thought disintegrated into its several elements. Theoretical and practical knowledge, which had been so successfully fused in the great systems of Democritus, Plato, and Aristotle, became separated. The whole tendency of the time was toward segregation. =1. The Abandonment of Metaphysical Speculation.= The theoretical side of philosophy, which had been so successfully completed by the great Greek masters, now became subordinated and almost completely lost to view. _Metaphysical speculation was neglected_ except as it threw light on the practical sciences――on ethics and the natural sciences. Knowledge was no longer loved for its own sake.