On this basis, in a healthy environment, science and energy might have reared a constructive rationalism; and for a time astronomy, in the hands of Aristarchos of Samos (third century B.C.), Eratosthenes of Cyrene, the second keeper of the great Alexandrian library (2nd cent. B.C.), and above all of Hipparchos of Nikaia, who did most of his work in the island of Rhodes, was carried to a height of mastery which could not be maintained, and was re-attained only in modern times. [738] Thus much could be accomplished by "endowment of research" as practised by the Ptolemies at Alexandria; and after science had declined with the decline of their polity, and still further under Roman rule, the new cosmopolitanism of the second century of the empire reverted to the principle of intelligent evocation, producing under the Antonines the "Second" School of Alexandria. But the social conditions remained fundamentally bad; and the earlier greatness was never recovered. "History records not one astronomer of note in the three centuries between Hipparchos and Ptolemy"; and Ptolemy (fl. 140 C.E.) not only retrograded into astronomical error, but elaborated on oriental lines a baseless fabric of astrology. [739] Other science mostly decayed likewise. The Greek world, already led to lower intellectual levels by the sudden ease and wealth opened up to it through the conquests of Alexander and the rule of his successors, was cast still lower by the Roman conquest. Pliny, extolling Hipparchos with little comprehension of his work, must needs pronounce him to have "dared a thing displeasing to God" in numbering the stars for posterity. [740] In the air of imperialism, stirred by no other, original thought could not arise; and the mass of the Greek-speaking populations, rich and poor, gravitated to the level of the intellectual [741] and emotional life of more or less well-fed slaves. In this society there rapidly multiplied private religious associations--thiasoi, eranoi, orgeones--in which men and women, denied political life, found new bonds of union and grounds of division in cultivating worships, mostly oriental, which stimulated the religious sense and sentiment. [742] Such was the soil in which Christianity took root and flourished; while philosophy, after the freethinking epoch following on the fall of Athenian power, gradually reverted to one or other form of mystical theism or theosophy, of which the most successful was the Neo-Platonism of Alexandria. [743] When the theosophic Julian rejoiced that Epicureanism had disappeared, [744] he was exulting in a symptom of the intellectual decline that made possible the triumph of the faith he most opposed. Christianity furthered a decadence thus begun under the auspices of pagan imperialism; and "the fifth century of the Christian era witnessed an almost total extinction of the sciences in Alexandria" [745]--an admission which disposes of the dispute as to the guilt of the Arabs in destroying the great library.