It was in Alexandria that during the third century B.C. the exact sciences reached the height of their development. All that was acquired through the incentive given later by the study of the exact sciences of antiquity during the Middle Ages through the medium of Arabic translations, and during the _Renaissance_ by means of newly discovered Greek originals of the ancient classics, was in the main due to the achievements wrought during this epoch.[8] That Alexandria should have been, during the Hellenistic period, the centre of this intensive, intellectual activity will be seen to have been a fact of great importance when we come to speak of this city as having been also the centre of the Jewish Dispersion. Alexandria[9] was, however, but the greatest example of many other new cities founded by Alexander, or through his inspiration, while a far greater number which were already in existence were hellenized through his instrumentality. With regard to these latter a fact of great importance must be noted; one effect of the entry of Hellenistic influence into the civic life of the “barbarians” was that the Greek came to know and understand his fellow-creatures of other nationalities; he saw that those whom he had always been taught to despise as not much better than semi-civilized savages, also had their forms of culture which likewise boasted of a hoary antiquity. The Greeks were, therefore, led to study the methods of thought, the customs and the beliefs of these “barbarians,” with the result that contempt was turned to admiration, and the Greeks came to regard the “barbarians” as brothers. Cynic and Stoic philosophers, “the Rousseaus of Hellenism” as Krüger very happily calls them, spoke of and taught a brotherhood of man, a new and wonderful thing; and a cosmopolitanism, hitherto unheard of, came into being.