Aristoxenus of Tarentum (Ἀριστόξενος ὁ Ταραντῖνος; born 375, fl. 335 BC) was a Greek Peripatetic philosopher, and a pupil of Aristotle. Most of his writings, which dealt with philosophy, ethics and music, have been lost, but one musical treatise, Elements of Harmony (Greek: Ἁρμονικὰ στοιχεῖα; Latin: Elementa harmonica), survives incomplete, as well as some fragments concerning rhythm and meter. The Elements is the chief source of our knowledge of ancient Greek music.
Aristoxenus was born at Tarentum (in modern-day Apulia, southern Italy) in Magna Graecia, and was the son of a learned musician named Spintharus (otherwise Mnesias). He learned music from his father, and having then been instructed by Lamprus of Erythrae and Xenophilus the Pythagorean, he finally became a pupil of Aristotle, whom he appears to have rivaled in the variety of his studies. According to the Suda, he heaped insults on Aristotle after his death, because Aristotle had designated Theophrastus as the next head of the Peripatetic school, a position which Aristoxenus himself had coveted having achieved great distinction as a pupil of Aristotle. This story is, however, contradicted by Aristocles, who asserts that he only ever mentioned Aristotle with the greatest respect. Nothing is known of his life after the time of Aristotle's departure, apart from a comment in Elementa Harmonica concerning his works.
His writings were said to have consisted of four hundred and fifty-three books, and dealt with philosophy, ethics and music.
Although his final years were in the Peripatetic school, and he hoped to succeed Aristotle on his death, Aristoxenus was strongly influenced by Pythagoreanism, and was only a follower of Aristotle in so far as Aristotle was a follower of Plato and Pythagoras. Thus, as Sophie Gibson tells us, "the various philosophical influences" on Aristoxenus included growing up in the profoundly Pythagorean city of Taras (Tarentum), home also of the two Pythagoreans Archytas and Philolaus, and his father's (Pythagorean) musical background, which he inculcated into his son.