Plato is one of the world's best known and most widely read and studied philosophers. He was the student of Socrates and the teacher of Aristotle, and he wrote in the middle of the fourth century B.C.E. in ancient Greece. Though influenced primarily by Socrates, to the extent that Socrates is usually the main character in many of Plato's writings, he was also influenced by Heraclitus, Parmenides, and the Pythagoreans.

The Athenian philosopher Plato (c.428-347 B.C.) is one of the most important figures of the Ancient Greek world and the entire history of Western thought. In his written dialogues he conveyed and expanded on the ideas and techniques of his teacher Socrates. The Academy he founded was by some accounts the world’s first university and in it he trained his greatest student, the equally influential philosopher Aristotle. Plato’s recurring fascination was the distinction between ideal forms and everyday experience, and how it played out both for individuals and for societies. In the “Republic,” his most famous work, he envisioned a civilization governed not by lowly appetites but by the pure wisdom of a philosopher-king.

Plato (428/427 - 348/347 BCE) is considered the pre-eminent Greek philosopher, known for his Dialogues and for founding his Academy north of Athens, traditionally considered the first university in the western world. Born Aristocles, son of Ariston of the deme Colytus, Plato had two older brothers (Adeimantus and Glaucon), who both feature famously in Plato's dialogue Republic, and a sister Potone. He is known by the nickname 'Plato' which, according to Diogenes Laertius, was given him by his wrestling coach because of his broad shoulders (in Greek 'Platon' means broad). His family was aristocratic and well-connected politically, and it seems Plato was expected to pursue a career in politics. His interests, however, tended more toward the arts and, in his youth, he wrote plays and, perhaps, poetry. When he was in his late teens or early twenties he heard Socrates teaching in the market and abandoned his plans to pursue a literary career as a playwright; he burned his early work and devoted himself to philosophy.

Viewed by many as the founding figure of Western philosophy, Socrates (469-399 B.C.) is at once the most exemplary and the strangest of the Greek philosophers. He grew up during the golden age of Pericles’ Athens, served with distinction as a soldier, but became best known as a questioner of everything and everyone. His style of teaching—immortalized as the Socratic Method—involved not conveying knowledge but rather asking question after clarifying question until his students arrived at their own understanding. He wrote nothing himself, so all that is known about him is filtered through the writings of a few contemporaries and followers, most of all, his student Plato. He was accused of corrupting the youth of Athens and sentenced to death. Choosing not to flee, he spent his final days in the company of his friends before drinking the executioner’s cup of poisonous hemlock.

Although Socrates left no written records concerning himself, it is possible to reconstruct a fairly accurate account of his life from the writings of his Greek contemporaries. Aristophanes caricatured him in a work called The Clouds. Xenophon in his Memorabilia expressed high praise for Socrates, with special reference to the method that he advocated for selecting the rulers of a state. Plato, to whom we are most indebted for information about Socrates, made him the chief character in many of his famous dialogs It is generally assumed that in Plato's earlier dialogs, the speeches attributed to Socrates are historical in the sense that they reproduce what Socrates actually said in the conversations he held with fellow Athenians. In the later dialogs, there is reason to believe that, at least in some instances, Plato was setting forth his own ideas by putting them into the mouth of Socrates. To what extent this was done is something that cannot be known with certainty.

Socrates is one of the few individuals whom one could say has so-shaped the cultural and intellectual development of the world that, without him, history would be profoundly different. He is best known for his association with the Socratic method of question and answer, his claim that he was ignorant (or aware of his own absence of knowledge), and his claim that the unexamined life is not worth living, for human beings. He was the inspiration for Plato, the thinker widely held to be the founder of the Western philosophical tradition. Plato in turn served as the teacher of Aristotle, thus establishing the famous triad of ancient philosophers: Socrates, Plato, and Aristotle. Unlike other philosophers of his time and ours, Socrates never wrote anything down but was committed to living simply and to interrogating the everyday views and popular opinions of those in his home city of Athens. At the age of 70, he was put to death at the hands of his fellow citizens on charges of impiety and corruption of the youth. His trial, along with the social and political context in which occurred, has warranted as much treatment from historians and classicists as his arguments and methods have from philosophers.

Socrates (469/470-399 BCE) was a Greek philosopher and is considered the father of western philosophy. Plato was his most famous student and would teach Aristotle who would then tutor Alexander the Great. By this progression, Greek philosophy, as first developed by Socrates, was spread throughout the known world during Alexander's conquests.