After the the Persian war The Delian league was created. Athens controlled this league gaining wealth and power which Sparta was unhappy about because without them then Athens would have never have been able to win the Persian war and Athens was being controlling
Sparta Marches to Athens, burning down there farms burning their food supplies outside of the city. Because of this Athens brings everyone behind the walls of the city. This lasted 2 years
Athens attacked Sparta
Sparta waited for two years as stratigising but then the plague hit Athens. 1/3 of the population died including there king, Pericles. Sparta didn't attack not wanting to catch the sickness
Sparta created a truce retreating from Athens but the peace didn't last long. 415 BCE the Athenians where angry with Sparta for keeping them behind the walls and for there people dying
Athens send 20,000 men to island of Sicily one of Sparta's allied wealthiest islands where Sparta gets a lot of the resources they don't have. But Sparta rushed in and Saved the Island defeating Athens
Afterwards Athens had lost confidence in there government and started questioning their values. That's when Scrates appeared with his beliefs and tried to educate Athens youth but later he was executed for it. After him was Pluto who wrote the republic, setting forth his version of a society placing people into three social classes, Farmers, warriors and ruling class. After him came his disciple Aristatle. He created the start of the scientific method and questioned the nature of the world.