Socrates and Plato
Socrates (469-399 BC) is the best example of a lover of wisdom who ever lived. Too poor to take the formal course of instruction from the Sophists, he thought for himself. He would engage other Athenians in debate and discussion, searching for the truth. Those who claimed to know were subjected to his rigorous dialectic, and often were made to look ridiculous. So he made enemies. He was not a friend of the Athenian democracy, which was something like mob rule, so he found himself, as an old man, in political trouble.
This trouble took the form of a suit--against Socrates. He was charged with teaching belief in false gods and corrupting the young. He was convicted, and executed by being forced to drink poison. Even during his last hours he carried on a philosophical dialogue with his students and friends about the immortality of the soul!
Plato (427-347 BC) turned out to be Socrates: best and most famous student, and indeed it is to Plato's writings that we owe most of what we know about Socrates. Plato took Socrates: dialectical search for definitions of such ideas as justice, beauty and goodness, and constructed a deep and sophisticated theory, the Theory of Forms, which held that all things in the visible world are only imperfect copies of the changeless Forms.
Plato also developed the doctrines that knowledge is recollection of the Forms by the soul, that virtue is knowledge, and that the soul is immortal, all of which probably originated with Socrates.
In the Republic Plato explains justice and presents his ideal state, ruled by the wise. His idealism, his faith in reason and order, his moral sensitivity and his literary genius have made him one of the great men of world history. Through St. Augustine his philosophy found its way into early Christianity.