The Peloponnesion Wars (there were two) were fought between the Greek city states of Athens and Persian. The two city states had been allied during the Persian Wars which had seen Persia eliminated from the Aegean Sea basin. The absence of the Persians meant that the Aegean could be turned into a private lake by any force with a strong navy. Athens had a strong navy and attempted to do just that by forming the Delian League, named for the island of Delos, considered a sacred site. Although the League had previously existed to fight the Persians, Athens now turned it to its own advantage. City-states within its influence were forced to join the league and pay tribute to Athens. Those who resisted were ruthlesslyput down. On occasion, Athens used its navy to defeat members of its own league.
Sparta was alarmed at the extension of Athenian power, and formed its own league, the Peloponessian League. The city state of Corinth had been allied with Sparta, but Athens tried to force it to join the Delian League. Several meetings were held between representatives of both Sparta and Athens but to no avail. Athens had been led by a brilliant but egotistical kinsman of Pericles known as Alcibiades. He led an attack on Sicily which proved disastrous, and he soon deserted to join Sparta. Immediately after he left, statues of Hermes, the Messenger God were emasculated throughout Athens. Alcibiades was blamed for the desecration.
The wars lasted thirty seven years, and were disastrous for both sides, with famine, plague, and devastating attacks. The historiuan Thucydides described the situation:
For never had so many cities been captured and destroyed, whether by the barbarians or by the Greeks who were fighting each other…Never had so many men been exiled or slaughtered whether in the war or because of civil conflicts.
Persia came into the war on the side of the Spartans, and Athens was defeated. In 404 B.C.E. the city walls of Athens were destroyed to the music of flute girls.
The only positive outcome of the wars was the development of historical writing, including Thucidides, mentioned above, and Heroditus, considered the father of history. Both city states were weakened by the war, and another power vacuum developed which was soon filled by Philip of Macedon, father of Alexander the Great.