The term “Epicureanism” means the philosophy of Epicurus (b. Samos c. 342–341 bce, d. Athens c. 271–270 bce) and the school founded by him. Epicurus was one of the most famous Greek philosophers of the Hellenistic period (which traditionally dates from the death of Alexander the Great [323 bce] to the Battle of Actium [31 bce]) and its influence on the history of Western philosophy is certainly decisive. Epicurus’s philosophy is organized into a coherent system, with parts that follow an unchangeable order oriented toward ethics; i.e., the end and the culmination to which philosophy aims: (1) canonic (i.e., the epistemological part of the system, which contains the criteria of truth based on the veracity of sensations); (2) physiology (i.e., the science of nature, which explains everything on the ground of atoms and void); (3) ethics (which promises the attainment of happiness through pleasure, which is the complete absence of pain). Although most of Epicurus’s works have been lost, a crucial source to rebuild his philosophy is Diogenes Laertius’s Lives and Opinions of Eminent Philosophers, Book 10, that preserved the “Testament” (§§ 16–21); the three doctrinal letters addressed to Herodotus (§§ 35–83, about the science of nature), to Pythocles (§§ 84–116, about celestial and meteorological phenomena), and to Menoeceus (§§ 121–135, about ethics); and forty “Principal Doctrines” (§§ 139–154, essentially about morals). A Vatican Library manuscript (Vat gr. 1950) also preserved eighty-one maxims (some are identical to Principal Doctrines; others are attributable to the Epicurean Metrodorus of Lampsacus): it is the so-called Gnomologium Vaticanum Epicureum (Vatican Sayings). The masterpiece of Epicurus devoted to the science of nature is Peri physeos (On Nature) in thirty-seven books, only a few fragmentary papyri of these have been found in the Villa dei Papiri in Herculaneum (Italy). Beyond the works by several Epicureans (such as Philodemus of Gadara) found in Herculaneum, Lucretius’s De rerum natura (Of the Nature of Things) and the monumental inscription on stone by Diogenes of Oinoanda (in Lycia) dated around 120 ce are very significant Epicurean sources. After establishing some “philosophical circles” in Mytilene and Lampsacus, Epicurus founded his main philosophical school, the “Garden” (Kepos), in Athens (307–304 bce). Many scholarchs succeeded Epicurus at the helm of the Garden, from Hermarchus of Mytilene (scholarch after Epicurus until about 250 bce) to Patron (before 50 bce); however, no clear information is available after that on the succession of Kepos leaders. Epicureanism was one of the most enduring philosophical schools of the ancient world. Up to the Imperial Age, it is possible to ascertain that Epicureanism was still active; it is well known, indeed, that one of the Imperial chairs created by Marcus Aurelius (176 ce) was of Epicurean philosophy.
