Plato, original name Aristocles, (427?–347 B.C. ), the Greek philosopher who built the foundations for later philosophy. His common name is the Latin form of the Greek Platan , which means “broad” (probably he was so named because of his broad shoulders). Plato was a superb literary artist; his writings, especially his Republic , are among the world's greatest classics. His union of content and style gives him a supreme place in the history of literature and thought.

Plato was born into a noble Athenian family. At the age of 20 he became a disciple of the philosopher Socrates. After Socrates was condemned to drink the poison hemlock in 399 B.C. Plato left Athens and traveled widely in Greece, Italy, Sicily, and probably Egypt and North Africa.

Plato returned to Athens in 387 and opened a school in a garden. Aristotle was his most noted student. Plato's Academy, as it was called, was the world's first university. (It existed until 529 A.D.)

About 40 writings are attributed to Plato, but about 14 are probably not his. Nearly all the works considered genuine are in dialogue form, usually with Socrates as the chief speaker. The Apology gives Socrates' defense at his trial. The Phaedo , which argues that belief in immortality is a rational faith, presents Socrates' final hours and death. The Gorgias is a plea for absolute right, as against expediency, in both private and public conduct. The Republic discusses the nature of justice, presents the ideal state, deal-with the theory of ideas, and touches on such subjects as ethics, esthetics, politics, economics, education, and psychology. The Laws , Plato's last work, discusses the nature of the state in practical terms.