=94.= An eminent pupil of Aristo was ERATOSTHENES of Cyrene, the grammarian, whom he won over from the Cyrenaic school. Eratosthenes undoubtedly represented the spirit of his teacher and of the Cynic school towards which he inclined, when he vehemently repudiated the prejudice which then divided mankind into Hellenes and barbarians[43]. He was invited by Ptolemy III (Euergetes) to be chief librarian of the Museum at Alexandria, and tutor to the crown-prince, and has left us an epigram in honour of this great patron of learning and philosophy[44]. Amongst other followers of Aristo we hear specially of APOLLOPHANES of Antiochia[45]. [Sidenote: Dionysius.] =95.= Alone amongst the hearers of Zeno DIONYSIUS of Heraclea abandoned his principles, and went over from the camp of virtue to that of pleasure. A painful disease of the eyes had made him abandon the doctrine that ‘pain is no evil[46].’ His secession was used by Antiochus as an argument against the doctrine of comprehension or certain knowledge[47]. That his life after he became a Cyrenaic was openly scandalous[48] we need not too readily believe: such accusations may easily be mere deductions from his supposed philosophic principles. Dionysius appears to have been a particular friend and admirer of the poet Aratus[49]. Of the less important hearers of Zeno we have the names of, amongst others, ATHENODORUS of Soli[50], CALLIPPUS of Corinth[50], POSIDONIUS of Alexandria[50], and ZENO of Sidon[50]. The last, if he existed, must be kept distinct from other Zenos, such as Zeno of Tarsus the pupil of Chrysippus, and Zeno of Sidon the Epicurean philosopher. [Sidenote: Cleanthes.]