Original: The Peloponnesian War, 431 to 404 B.C., was an Ancient Greek war, fought by Athens and its empire against the Peloponnesian League, led by Sparta.
Simplified: The Peloponnesian War (431–404 BC) was an Ancient Greek military conflict, fought by Athens and its allies, that supported Democracy, against the Peloponnesian League, led by Sparta, that supported Oligarchy.