In 405 BC the Spartan general Ly sander defeated the Athenian fleet in battle. With the fleet defeated, the people in the city of Athens began to starve. They did not have the army to take on the Spartans on land. In 404 BC the city of Athens surrendered to the Spartans.
The city-states of Corinth and Thebes wanted the city of Athens destroyed and the people enslaved. However, Sparta disagreed. They made the city tear down its walls, but refused to destroy the city or enslave its people.