Plato lived in an era when Athens flourished and declined.

The victory of the Greek-Persian war laid the foundation for the prosperity of Athens. The Tyrol League formed in the war centered on Athens and formed the Athenian Empire. After the war, Athens was unprecedentedly powerful economically, culturally and militarily.

This prosperity has declined in the Pareto era because of the Greek civil war, that is, the Peloponnesian withdrawal war. This protracted war swept almost the whole of Greece. This is actually a hegemonic war between Athens and Sparta. Sparta lost the leadership of the anti-Persian war alliance in the late Persian war and was replaced by the Athenians. After the establishment of the Romanian Union, the Athenian Empire was gradually formed. The impact of the war on Athens: First, the economy suffered a blow. The status of Athens as a commercial center has been shaken, and the economy is inevitably declining. Second, the status has declined. The failure of the war made Athens lose its leading position in the Greek world and had to admit that Sparta was the overlord of Greece. The influence is weakened. Third, the democratic system has been challenged. Fourth, the decline of ethics.