It would have been hard for Epicurus to be involved in philosophy and never to have heard of Aristotle. It would be a bit like being a Roman historian and never having heard of Mommsen. Or a mathematician never having heard of Russell. Aristotle was the founder of the Peripatetic school centered at Athens but influential throughout the entire Greek world, and the effects of Aristotle's teaching would have been felt by any educated Greek-speaker. Moreover, Epicurus was twenty years old when Aristotle died. He returned to Athens (the place of his father's citizenship) in 324/3 to do two years of mandatory military service and moved to Colophon around 322. He therefore would have been in Athens right around the time of Aristotle's flight to Euboea following Alexander's death. There is no evidence from the ancient biographers or the philosophical tradition that Epicurus ever actually met Aristotle, but he certainly was aware of his teachings and lived in Athens where the Academy and Peripatetics were based from 307 until his death. Diogenes Laertius claims that Aristotle was teaching in Calchis already by the time Epicurus came to Athens, but he also says that Epicurus was taught by the Academic Xenocrates. This should not be surprising--Athenian philosophy at this period was dominated by Plato's Academics and Aristotle's Peripatetics, and in the course of Epicurus' philosophical education he would have been closely exposed to both. The influence was probably strongest from the Academics, as Diogenes Laertius suggests. The Epicureans and Stoics both claimed to be the "true" heirs of Plato, and the similarities between their philosophy and that of the Peripatetics is in large part due to their common descent from the Academy.