Question: Plutarch of Athens wrote commentaries on what Greek philosopher, whose writings constitute the first comprehensive system of Western philosophy?
Context: 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. Plutarch of Athens (Greek: Πλούταρχος ὁ Ἀθηναῖος ; c. 350 – 430 AD) was a Greek philosopher and Neoplatonist who taught at Athens at the beginning of the 5th century.  He reestablished the Platonic Academy there and became its leader.  He wrote commentaries on Aristotle and Plato, emphasizing the doctrines which they had in common. Augustine of Hippo ( or ; 13 November 354 – 28 August 430) was an early North African Christian theologian and philosopher whose writings influenced the development of Western Christianity and Western philosophy.  He was the bishop of Hippo Regius in north Africa and is viewed as one of the most important Church Fathers in Western Christianity for his writings in the Patristic Era.  Among his most important works are "The City of God" and "Confessions." Anaxagoras ( ; Greek: Ἀναξαγόρας , "Anaxagoras", "lord of the assembly";  510 – c. 428  BC) was a Pre-Socratic Greek philosopher.  Born in Clazomenae in the Persian Empire (modern-day Urla, Turkey) Anaxagoras was the first to bring philosophy to Athens.  According to Diogenes Laertius and Plutarch, in later life he was charged with impiety and went into exile in Lampsacus; the charges may have been political, owing to his association with Pericles, if they were not fabricated by later ancient biographers. Adrastus of Aphrodisias (Greek: Ἄδραστος ὁ Ἀφροδισιεύς ; fl.  2nd century) was a Peripatetic philosopher who lived in the 2nd century AD.  He was the author of a treatise on the arrangement of Aristotle's writings and his system of philosophy, quoted by Simplicius, and by Achilles Tatius.  Some commentaries of his on the "Timaeus" of Plato are also quoted by Porphyry, and a treatise on the "Categories" of Aristotle by Galen.  None of these have survived.  He was a competent mathematician, whose writings on harmonics are frequently cited by Theon of Smyrna in the surviving sections of his "On Mathematics Useful for the Understanding of Plato".  In the 17th century, a work by Adrastus on harmonics, Περὶ Ἁρμονικῶν ("On Harmonics"), was said by Gerhard Johann Vossius to have been preserved, in manuscript, in the Vatican Library, although the manuscript appears to be no longer extant, if indeed this was not an error on Vossius' part. The Rorschach Performance Assessment System (R-PAS) is a scoring method to be used with the Rorschach inkblot test.  This system is being developed by several members of the Rorschach Research Council, a group established by John Exner to advance the research on the Comprehensive System, the most widely used scoring system for the Rorschach.  Following Exner's death, the council admitted that the current Comprehensive System scoring was in need of revision.  But rather than updating the existing system, a new system was established.  The introduction of a new system, as opposed to modification of the existing system, has caused some controversy. Phaenias of Eresus (Ancient Greek: Φαινίας ὁ Ἐρέσιος , "Phainias"; also Phanias) was a Greek philosopher from Lesbos, important as an immediate follower of and commentator on Aristotle.  He came to Athens about 332 BCE, and joined his compatriot, Theophrastus, in the Peripatetic school.  His writings on logic and science appear to have been commentaries or supplements to the works of Aristotle and Theophrastus.  He also wrote extensively on history.  None of his works have survived. A History of Western Philosophy is a 1945 book by philosopher Bertrand Russell.  A survey of Western philosophy from the pre-Socratic philosophers to the early 20th century, it was criticised for Russell's over-generalization and omissions, particularly from the post-Cartesian period, but nevertheless became a popular and commercial success, and has remained in print from its first publication.  When Russell was awarded the Nobel Prize for Literature in 1950, "A History of Western Philosophy" was cited as one of the books that won him the award.  Its success provided Russell with financial security for the last part of his life. Dexippus (Greek: Δέξιππος ; fl.  350) was a Greek philosopher, a pupil of the Neoplatonist Iamblichus, belonging to the middle of the 4th century AD.  He wrote commentaries on Plato and Aristotle of which one, an explanation and defense of the Aristotelian Categories, is partially extant.  In this work Dexippus explains to one Seleucus the Aristotelian Categories, and endeavours at the same time to refute the objections of Plotinus.  He also advocated the harmony of the philosophies of Plato and Aristotle. Aspasius ( ; Greek: Ἀσπάσιος ; c. 80 – c. 150 AD) was a Peripatetic philosopher.  Boethius, who frequently refers to his works, says that Aspasius wrote commentaries on most of the works of Aristotle.  The following commentaries are expressly mentioned: on "De Interpretatione", the "Physica", "Metaphysica", "Categoriae", and the "Nicomachean Ethics".  A portion of the commentary on the "Nicomachean Ethics" (books 1, 2, 4, 7, and 8) is extant.  The Greek text of this commentary has been published as "Commentaria in Aristotelem Graeca" (CAG) vol.  19.1, and David Konstan has published an English translation.  It is notable as the earliest extant commentary on any of Aristotle's works.  From Porphyry, who also states that Aspasius wrote commentaries on Plato, we learn that his commentaries on Aristotle were used in the school of Plotinus.
Answer: Aristotle