Plato had an enormous influence on the development of Western philosophy. The Athenian thinker came from a prominent family and received an education worthy of his class. At this time, a majority of the aristocratic children of Athens went on to political careers. Plato was disillusioned with politics, in large part due to the condemnation and execution of his teacher Socrates, in 399 B.C. Socrates remained the central influence on Plato's thought, and many of the younger philosopher's works take the form of a dialogue between himself and Socrates. Following three trips to Southern Italy and Sicily, where he learned of the mathematics and ideas of Pythagoras and his circle, Plato founded his academy on the outskirts of Athens, at a site honoring Academus, a local hero. Philosophers from all over the Greek world came to live and study there, at what was to become a sort of early university. Plato's greatest student was Aristotle, who came to study at the academy at age 17 and remained there for the last 20 years of Plato's life. Plato is the earliest Western philosopher whose works have survived in their entirety, and many of these rank among the greatest works in the canon of Western literature.