Plutarch of Athens wrote commentaries on what Greek philosopher, whose writings constitute the first comprehensive system of Western philosophy?
Plutarch of Athens:  He wrote commentaries on Aristotle and Plato, emphasizing the doctrines which they had in common. Aristotle:  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.
Aristotle