Sophrosyne an important topic for Plato. It is main subject of the dialogue "Charmides", wherein several definitions are proposed but no conclusion reached; however the dramatic context connotes moral purity and innocence. An etymological meaning of sophrosyne as "moral sanity" is proposed in "Cratylus" 411e. Plato's view of sophrosyne is related to Pythagorean "harmonia" ("Republic" 430e−432a, 442c) and closely linked with Plato’s tripartite division of the soul: "sophrosyne" is the harmonious moderation of the appetitive and spirited parts of the soul by the rational part (e.g., "Phaedrus" 237c−238e). For the Stoic, Zeno of Citium, "sophrosyne" is one of the four chief
Ancient Greek phonology present in English or Modern Greek, such as a three-way distinction between voiced, voiceless, and aspirated stops (such as , as in English "bot, spot, pot"); a distinction between single and double consonants and short and long vowels in most positions in a word; and a word accent that involved pitch. Koine Greek, the variety of Greek used after the conquests of Alexander the Great in the fourth century BC, is sometimes included in Ancient Greek, but its pronunciation is described in Koine Greek phonology. For disagreements with the reconstruction given here, see below. Ancient Greek was a pluricentric language,