The city-state of Athens and its allies were defeated by Sparta in the Peloponnesian War.
Athens and its allies were defeated by Sparta in the Peloponnesian War.
Sparta defeated Athens .
If you are talking about what we usually call the Peloponnesian War 431 to 404 BCE, Sparta led the Peloponnesian League which defeated the Athenian Empire in that war.
Generally, it was Athens (with its navy) versus Sparta (with its army). This was a war (from 431 to 404 BC) in which Athens and its allies were defeated by the Peloponnesian League, including Sparta.
The Peloponnesian League, led by Sparta, defeated the Athenian league/empire.
The Spartan alliance with the help of Persia defeated the Athenian alliance.
No single city-state won the war. Sparta and its allies defeated Athens and its allies.
Led the Peloponnesian League.
Athens won the first Peloponnesian War but Sparta won the second war
No city won. The Sparta alliance with Persian backing defeated the Athens alliance or empire.
. . . the Peloponnesian War .
The war that ended the Golden Age was the Peloponnesian War