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
Sophrosyne virtues. Later Stoics like Musonius Rufus, Seneca, Epictetus, and Marcus Aurelius took a practical view of "sophrosyne" and share a definition of it as the restraint of the appetites. Demophilus, a Pythagorean philosopher of uncertain date, wrote: "the vigor of the soul is sophrosyne, the light of a soul free of disturbing passions." (Ρώμη ψυχής σωφροσύνη αύτη γαρ ψυχής απαθούς φώς εστιν.) Cicero considered four Latin terms to translate "sophrosyne": "temperantia" (temperance), "moderatio" (moderateness), "modestia" (modesty) and "frugalitas" (frugality). Through the writings of Lactantius, St. Ambrose and St. Augustine, the virtue's meaning as temperance or "proper mixture" became the dominant