Plutarch of Athens wrote commentaries on what Greek philosopher, whose writings constitute the first comprehensive system of Western philosophy?
Aristotle Aristotle ( ; Greek: Ἀριστοτέλης , , "Aristotélēs"; 384–322 BC) was an ancient Greek philosopher and scientist born in the city of Stagira, Chalkidice, on the northern periphery of Classical Greece. His father, Nicomachus, died when Aristotle was a child, whereafter Proxenus of Atarneus became his guardian. At seventeen or eighteen years of age, he joined Plato's Academy in Athens and remained there until the age of thirty-seven (c. 347 BC). His writings cover many subjects – including physics, biology, zoology, metaphysics, logic, ethics, aesthetics, poetry, theater, music, rhetoric, linguistics, politics and government – and constitute the first comprehensive system of Western philosophy. Shortly after Plato died, Aristotle left Athens and, at the request of Philip II of Macedon, tutored Alexander the Great beginning in 343 BC.
Cleanthes Cleanthes ( ; Greek: Κλεάνθης "Kleanthēs"; c. 330 BC – c. 230 BC), of Assos, was a Greek Stoic philosopher and successor to Zeno of Citium as the second head ("scholarch") of the Stoic school in Athens. Originally a boxer, he came to Athens where he took up philosophy, listening to Zeno's lectures. He supported himself by working as a water-carrier at night. After the death of Zeno, c. 262 BC, he became the head of the school, a post he held for the next 32 years. Cleanthes successfully preserved and developed Zeno's doctrines. He originated new ideas in Stoic physics, and developed Stoicism in accordance with the principles of materialism and pantheism. Among the fragments of Cleanthes' writings which have come down to us, the largest is a "Hymn to Zeus". His pupil was Chrysippus who became one of the most important Stoic thinkers.