Aristotle (384–322). Unlike Socrates and Plato, Aristotle was not an Athenian citizen. He was born at Stagira in Thrace, a region in northern Greece near Macedonia. He came to Athens about 368 and studied at the Academy until Plato's death in 347. When Plato's nephew became head of the Academy, he left Athens, married Pythias, and they had a daughter. In 343, Philip of Macedón invited Aristotle to tutor his son, Alexander. When the young Alexander succeeded his assassinated father in 336, Aristotle returned to Athens and founded his own school, the Lyceum. After Pythias died, he shared his home with Herpyllis and fathered a son, Nicomachus, who may have edited the famous Nicomachean Ethics. Shortly after Alexander's death, anti-Macedonian sentiment was on the rise, forcing Aristotle to leave Athens for a family estate on an island, where he died in 322, leaving a will that provided for Herpyllis and their son. Although he also wrote dialogues for the general public, only fragments survive. Fortunately, many of his scholarly works in logic, philosophy of nature, ethics, rhetoric, politics, and literary criticism do survive thanks in large part to the editorial work of Andronicus of Rhodes in the first century B.C.E. Aristotle was the first to produce treatises devoted to ethics and to him we owe the idea that [ethics] is not simply a way of living and acting but a field worthy of academic study.
Chrysippus (280–207). After Cleanthes, who succeeded Zeno as head of the Stoic school, died, Chrysippus took over and became the most influential thinker during its Greek (pre-Roman) history. He wrote scores of books, though none survive. Fortunately, his ideas, which often advance and organize the doctrines of Zeno and