Athens wealth, prestige, and power was not well liked by other city states. Sparta takes exception to the arrogance and stolen treasury of the Athenians.
Athens had the stronger Navy. Pericles strategy was to avoid land battles and strike Sparta and its allies from the sea.
Sparta had a stronger Army. Spartans marched on Athenian territory and burned their food supply.
415 BC Athenians sent a huge fleet carrying more than 20,000 men to the island of Sicily. Destroy Syracuse (one of Sparta’s allies). Athenians were able to fend of Spartan attacks for 9 years before their allies surrendered to Sparta and the empire fell.
After the Peloponnesian War, Athenians lost faith in their government and began to question their values.
“Effects of the Peloponnesian War.” Courses.lumenlearning.com,courses.lumenlearning.com/ suny-hccc-worldhistory/chapter/effects-of-the-peloponnesian-war/.
After the Pelopennesian War, Sparta had a short-lived military and political dominance over other city-states.