How did the Persian War lead to the Peloponnesian War

When the Greek city-states banded together to repel the Persianinvasions, Athens and Sparta emerged as Persia’s leading opponents.Athens’ fleet destroyed the Persian Navy, while the Spartan Armyled the defense on land. Once they had disposed of the Persianthreat, the two former allies grew suspicious of one another. Asimilar thing happened after Russia and the US allied to defeatNazi Germany, but became suspicious of one another after defeatingHitler in WWII.

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After defeat of the Persian invasion, Sparta proposed evacuatingthe Greek cities within the Persian Empire back to mainland Greeceto remove the cause of war between Persia and the Greeks (this wasactually done over two thousand years later after World War 1).

Athens had a better idea – to form an anti-Persian league fromthese cities in Persian territory, and guarantee the citiesindependence and protection. The cities could either contributewarships or pay the League for the upkeep of warships. Most gavemoney, and most of the money went to maintain Athens’ superiorfleet. Sparta, always inwards looking, stayed home in its ownterritory.

Athens was involved in several wars between Greek cities, andimagined itself impregnable, with the alliance fleet and its citywalls at home, and became a standover power, intervening as itpleased. The cities of the Peloponnese resented this and looked toSparta to lead resistance to Athenian domination.

After flashpoints at Corcyra and Potidaia, Athens took punitiveaction against its neighbour Megara, which was a member of theSpartan-led Peloponnesian League. Sparta demanded on behalf of theLeague that Athens cease action against Megara and with noresponse, warfare was opened – a bitter and devastating 27-yearstruggle which extended through the Greek world from Sicily to AsiaMinor.