Politeia

Plato's work on the ideal state and the structure of the human soul, centered on the four cardinal virtues.

The Politeia is Plato's principal work on political theory and the doctrine of justice. It establishes the four cardinal virtues — wisdom, courage, temperance (sophrosyne), and justice — as foundational virtues for both the state and the human psyche. The Stoics adopted this framework and integrated it into their ethics of virtue.