Athens took control of the Delian Legue. After they did this, they made the other city-states pay taxes. Athens grew in wealth and power. The other city-states did not like this.
Peace?
The Spartans were so unhappy that they decides to march into Athens. When they got to Athens, they burned all the crops and surrounding countryside. All the citizens in Athens were brought into the city walls for protection. This lasted two years.
Sicily
The second year inside the city walls, a plague strikes. Because the people were so close together, the plague killed 1/3 of the population. Part of this 1/3 was their ruler Pericles.
Sparta's Victory
After the plague, the Spartans and Athens deiced on peace. This peace didn't last long. The Athenians were still extremely mad at Sparta for trapping them and losing 1/3 of their population.
The Athenians wanted their revenge. In 415 BCE, they sent a huge fleet of 20,000 men to the island of Sicily. Sicily was one of the main providers for Sparta. The Athenians planned of destroying Sicily.
The Spartans came to Sicily to fight Athens. Spartan won the battle, leaving Athens low in confidence. after the war, Athenians started to lose confidence in their government. This is when Philosopher started to appear.