Alexander had scarcely completed his twentieth year when the assassination of his father, by Pausanias, one of the officers of the guard, called him to the throne. Aristotle, however, continued to reside at the court two years longer; when some misunderstanding having arisen, he left the young monarch at the commencement of his celebrated expedition into Asia, and returned to Athens. It has been alleged that he accompanied his former pupil as far as Egypt; but the fact is not certain, although circumstances would seem to render it probable. He was well received at Athens, on account of the benefits which Philip had conferred, for his sake, on the inhabitants of that city; and, obtaining permission from the magistrates to occupy the Lyceum, a large enclosure in the suburbs, he proceeded to form a school. It was his custom to instruct his disciples while walking with them; and for this reason the new sect received the name of Peripatetics, or walking philosophers. In the morning he delivered his acroatic lectures to his select pupils, imparting to them the more abstruse parts of metaphysical science; and in the evening gave to his visiters or the public at large exoteric discourses, in which the subjects discussed were treated in a popular style. As the Lyceum soon acquired great celebrity, scholars flocked to it from all parts of Greece. Xenocrates, who shared with him the lessons of Plato, had by this time succeeded Speusippus in the Academy, and it has been alleged that Aristotle established his seminary in contemptuous opposition; observing, that it would be shameful for him to be silent while the other taught publicly. But although the rival sages of those days cannot be supposed to have been influenced by a gentler spirit than animates those of our own times, there is no reason for attributing to the Stagirite in this matter any other motive than a laudable desire of seeking his own interest by communicating knowledge to those who were desirous of receiving it. In this manner he gave public lectures at Athens thirteen years, during the greater part of which time he did not cease to correspond with Alexander. That celebrated prince had placed at his disposal several thousand persons, who were occupied in hunting, fishing, and making the observations which were necessary for completing his History of Animals. He is moreover said to have given the enormous sum of 800 talents for the same purpose; while he also took care to send to him a great variety of zoological specimens, collected in the countries which he had subdued.