The school of Aristotle in the Lukeion differed little in its methods from the school of Plato in the Akademeia. He had been a pupil of Plato for twenty years before he began to teach on his own account. He used to give instruction walking up and down in the walks of the Lukeion. In his earlier period, at any rate, he seems to have taught rhetoric, and taught it in Isocratean fashion: we hear of him setting a theme, on which he and the pupils delivered harangues “in rhetorical fashion.” Later the school became a home of universal knowledge and research; in this respect Aristotle is the heir of the much-abused Sophists. He adopted Xenokrates’ custom of appointing one of the pupils to be Archon of the school for ten days, and then another: this system must have relieved him of much petty business.[589] He delivered two courses of lectures daily: one in the morning on abstruse subjects to picked pupils; and the other in the afternoon, open to all comers and more intelligible in matter and manner.[590] His fame as a teacher was sufficient to win him the honour of being chosen to be Alexander’s tutor, and he seems to have retained his pupil’s respect, if not perhaps his affection. Aristotle, dreaming of a tiny city-state, and Alexander, dreaming of a world-empire and carrying out his dream, are an ill-assorted pair. What would Plato have given for the chance of educating such a Philosopher-king? That there were bitter feuds between the various educational leaders in Athens, goes without saying. A Hellene could no more brook a rival than could an Italian of the Renaissance. Isokrates attacks Plato,[591] Plato Isokrates, and then their pupils take the quarrel on into the next generation. Both attack with equal animus the wandering Sophists and the Eristics, who retaliated with vigour. A would-be pupil must have found it hard to choose a professor under whom to study, when so much evil had been spoken of them all.[592] * * * * * The schools of Rhetoric and of Philosophy were only for the rich and the leisured classes: the poor had neither the time nor the money requisite for attending them. But they were not wholly debarred from the higher knowledge. There were still Sophists lecturing for advertisement in public places. Still more, there were books, which were beginning to be both numerous and cheap: every Athenian could read. How important a part books were beginning to take in national education may be seen from the works of Isokrates and Plato, who are both excessively indignant at the intrusion of such a rival.