In his youth he had every intention of devoting himself to politics. He was brought by his father to Socrates when in his twentieth year, and enjoyed intimate friendship with him for eight years. It is related that Socrates dreamt on the preceding night that he had a young swan perched on his knees, whose wings quickly developed, and which then flew up to heaven, singing the sweetest songs. Many such incidents are mentioned by the ancients, and they bear witness to the deep reverence and love with which both contemporaries and those of later times regarded the calm dignity of Plato, and that loftiness of demeanour which he combined with extreme simplicity and lovableness, traits of character which won for him the name of “the divine.” Plato did not content himself with the society and wisdom of Socrates, but studied in addition the older philosophers, particularly Heraclitus. Aristotle (Met. I. 6) states that Plato, before he ever came to Socrates, associated with Cratylus, and had been initiated into the doctrines of Heraclitus. He also studied the Eleatics, and very particularly the Pythagoreans, and he frequented the society of the most noted Sophists. Thus deeply immersed in Philosophy, he lost his interest in poetry and politics, and gave them up altogether, that he might devote himself entirely to scientific pursuits. He fulfilled, like Socrates, his term of military service as an Athenian citizen, and is said to have taken part in three campaigns.[3] We have already mentioned (Vol. I. p. 448) that, after Socrates was put to death, Plato, like many other philosophers, fled from Athens, and betook himself to Euclides at Megara. Leaving Megara before long, he travelled first to Cyrene in Africa, where he turned his attention specially to mathematics, under the guidance of the celebrated mathematician Theodoras, whom he introduces as taking part in several of his dialogues. Plato himself soon attained to high proficiency in mathematics. To him is attributed the solution of the Delian or Delphic problem, which was proposed by the oracle, and, like the Pythagorean dogma, has reference to the cube. The problem is, to draw a line the cube of which will be equal to the sum of two given cubes. This requires a construction through two curves. The nature of the tasks then set by the oracles is very curious; on this particular occasion application had been made to the oracle in a time of pestilence, and it responded by proposing an entirely scientific problem; the change indicated in the spirit of the oracle is highly significant. From Cyrene Plato went to Italy and Egypt. In Magna Græcia he made the acquaintance of the Pythagoreans of that day, Archytas of Tarentum, the celebrated mathematician, Philolaus and others; and he also bought the writings of the older Pythagoreans at a high price. In Sicily he made friends with Dion. Returning to Athens, he opened a school of Philosophy in the Academy, a grove or promenade in which