5. ANTI-NEO-PLATONIC TENDENCIES.--While the Neo-Platonism of Alexandria introduced into Greek philosophy Oriental ideas and tendencies, other positive and practical doctrines also prevailed, founded on common sense and conscience. First among these were the tenets of the Stoics, who owed their system mainly and immediately to the teaching of Epictetus (fl. 60 A.D.), who opposed the Oriental enthusiasm of the Neo-Platonists. He was originally a slave, and became a prominent teacher of philosophy in Rome, in the reign of Domitian. He left nothing in writing, and we are indebted for a knowledge of his doctrines to Arrian, who compiled his lectures or philosophical dissertations in eight books, of which only four are preserved, and the "Manual of Epictetus," a valuable compendium of the doctrines of the Stoics. The Emperor Marcus Aurelius not only lectured at Rome on the principles of Epictetus, but he left us his private meditations, composed in the midst of a camp, and exhibiting the serenity of a mind which had made itself independent of outward actions and warring passions within. Lucian (fl. 150 A.D.) may be compared to Voltaire, whom he equaled in his powers both of rhetoric and ridicule, and surpassed in his more conscientious and courageous love of truth. Though the results of his efforts against heathenism were merely negative, he prepared the way for Christianity by giving the death-blow to declining idolatry. Lucian, as a man of letters, is on many accounts interesting, and in reference to his own age and to the literature of Greece he is entitled to an important position both with regard to the religious and philosophical results of his works, and to the introduction of a purer Greek style, which he taught and exemplified. Longinus (fl. 230 A.D.), both as an opponent of Neo- Platonism and as a sound and sensible critic, occupies a position similar to that of Lucian, in the declining period of Greek literary history. During a visit to the East, he became known to Zenobia, queen of Palmyra, who adopted the celebrated scholar as her instructor in the language and literature of Greece, her adviser and chief minister; and when Palmyra fell before the Roman power he was put to death by the Roman emperor. To his treatise on "The Sublime" he is chiefly indebted for his fame. When France, in the reign of Louis XIV., gave a tone to the literary judgments of Europe, this work was translated by Boileau, and received by the wits of Paris as an established manual in all that related to the sublime and beautiful.