PLATO (Gr. 70.67rwv, abroad,* a sobriquet given by Ariston, a teacher in athletics, and re ferring probably to Plato's broad shoulders), was born in Athens in the deme of Collytus, in 427 B.C., of aristocratic parentage, and died there in 347. According to an ancient tradition he was born on the 7th of Thargelion, Apollo's Day, which, in Olympiad 88.1 (accepting the Metonian canon), fell on 29 May, Julian calen dar. His original name was Aristocles, the name of his grandfather. His father's name was Ariston, of the line of Codrus, last of the kings of Athens, and his mother was Perictione, of the line of Solon, greatest of the Athenian archons. In many respects Solon was Plato's political exemplar, for Solon was at once philos opher and statesman. Plato distinguished him self in his early youth as an athlete, having wrestled in the Isthmian games at Corinth, and there is a doubtful tradition that he was once victor at Olympia. Before he was 20 he had written dramatic and lyric verse assiduously and with success. The most important event in his earlier life was his meeting with Socrates in 407. This event was decisive for his later career. He had already studied philosophy un der the Heraclitean Cratylus, but from 407 to the death of Socrates in 399 he was entirely absorbed in the- dialeetic of his new master, whose chief disciple and most complete inter preter he became. Immediately after the death of Socrates in prison (Plato, owing to illness, was not present), the disciple went to Megara, where, with his friend Euclid, he studied the Eleatic philosophy. After a brief residence in Megara, it is probable that he returned to Ath ens, and thereafter made extensive journeys to Egypt, Cyrene in Africa, Italy and Sicily. In Cyrene he visited the mathematician Theodorus. In Italy he was befriended by the famous ruler, Pythagorean philosopher and military leader, Archytas of Tarentum. In Sicily he formed an intimate friendship with Dion, brother-in-law of the elder Dionysius. Dionysius, then ruler of Syracuse, was offended by Plato's free criticism of the government, and turned him over to the Lacedamonian Ambassador, Pollio, to be sold as a slave. He was brought to 2Egina, where Anniceris (of the Cyrenaic school) ransomed him. After his release a plot of ground hard by the academy was bought for the use Of Plato's school, which then took the name of the adjoining gymnasium (academy). Plato estab lished his academy in 387 and presided over it until his death in 347. The foundation of the academy thus dates from the exact middle of his life. Two later journeys were made to Sicily, one in 367, on the accession of Dionysius the Younger, and one in 361, both for purpose of political experiment, but without success. Indeed, on the last visit his life was put in jeopardy by the distrust of Dionysius. There after he made no further attempts in practical statescraft, but carried forward continuously his scientific and literary work at the academy, where, in his early teaching, he employed a dia logic method (after the manner of his master, Socrates), and later the more dogmatic lecture. He died in 347 (according to tradition on his birthday, having thus completed exactly four score years), as Cicero says, scribens, in hand* (De Senectute, v. 13). His tomb near the academy, in the Ceramicus, was seen at the beginning of the Christian era.
No work of Plato known to an tiquity has been lost. On the contrary, the present corpus contains more than the genuine list of works. The traditional Platonic canon of Thrasyllus in nine tetralogies, accepted entire by Grote) contains 36 works (counting the letters as one), divided into 56 books. The
works are written almost entirely (excepting the 'Apology') in dialogue, a form which grew out of the Socratic conversations, which these writings purport to reproduce. They are not systematic treatises, but rather essays, the earlier of which are more peirastic and the later more dogmatic (cf. Pater's 'Plato and Platonism,' pp. 157-159). Their chronology represents the gradual philosophical evolution of Plato's own mind, and not any preconceived pedagogical plan. Regarding the determination of the se quence or dates of the dialogues, no consensus of opinion among Platonic scholars has been reached. The most important dialogues are the 'Symposium' (on Love), the (Phzdo' (on the Immortality of the Soul), the (Republic' (on the Ideal State), the (Thmetetue (on the Na ture of Knowledge), and the (Timmus) (on the Nature of the Physical World). Three periods of composition may be differentiated, namely: (1) A Socratic or Ethical period, in which the anti-sophistic dialogues were written. This period may be regarded as extending from 398 to 387, that is, from the beginning of Plato's philosophical writing to the opening of the academy; (2) a Metaphysical and Constructive period, in which Plato builds the Socratic con cept into its metaphysical form, develops the theory of ideas, invents his great myths, con structs the ideal state, and reaches the climax of his intellectual and literary genius — a period extending from 387 to 360; (3) a third period, marked by increasing mysticism and decreasing literary and philosophic power, a growing as cendency of Pythagoreanism and mathematical symbolism, a less daring civic ideal, a more dogmatic and less versatile manner of utterance and a greater emergence of religious interest — a period extending from the last Sicilian jour ney, or about 360, to his death in 347. See PLATO'S REPUBLIC; SYMPOSIUM; PLATONISM.
I. The Socratic and Anti-Sophistic Group, 398-387: (1) (2) ; (3) (4) ; (5) ; (6) 'Hippias II' ; (7) (8) ; (9) • (10) (11) (12) Books I and II; or, in the pagination of Stephanus, from 327 to 368 A.
II. The Metaphysical and Constructive Group, 387-360: (13) (14) posium>; (15) (16) Book II, 368 A to Book V (inclusive), and Books VIII-X; (17) (Phmdrus' ; (18) (The wtetus' • (19) (Parmenides); (20) Books VI VII, and reconstruction and unifica tion of the entire work, Books I-X; (21) (22) (23) (Philebus.' III. The and Politico religious Group, 360-347: (24) (Timmus); (25) ; (26) (Laws.' The following are spurious: I and II,' (Hipparchus,) (Clitophon,' (Theages,' (Epinomis,) (Letters,' (Hippias I,' (Demodocus,' (De Justo,> (De Vir tute,' (Tinneus Locrus,' EDMONS.—Aldus Manutius, first printed edition in Greek, folio (Venice 1513) ; Stephanus (with Latin translation, 3 vols., Paris 1578; the pagination of this edition is the basis of all modern references to the Platonic writings) ; Bekker (10 vols., Berlin 1816-23) ; Stallbaum (10 vols., Leipzig 1821 ff.) ; Baiter, Orelli and Winckelmann (2 vols., Zurich 1839-42; smaller edition in 21 vols.) ; Hermann (Teubner edition, 6 vols., new ed., Leipzig 1873 ff.) ; Schanz (Tauchnitz edition, incom plete, Leipzig 1875 ff.) ; Burnet (Oxford edi tion, incomplete, but most convenient, best printed and latest criticism, Oxford 1899 ff.).