What were the causes and effects of the Peloponnesian War on the Greek city-states

Athens had converted the anti-Persian league into an empire after peace had been arranged with Persia, by continuing to collect the financial levies and applying it for its own purposes – beautifying Athens and keeping half its citizens on the public payroll from the proceeds, and maintaining a dominant navy.

It also meddled in the affairs of the Greek cities which were not within its sway, using the navy to gather the taxes from the cities in its own empire. These cities not in its empire formed their own Peloponnesian League led by Sparta to oppose Athens, and the result was a call on Athens to desist over several disputes – among them Potidaia, Corcyra and Megara.

The Megara problem was its being banned from trading within the Athenian empire, which would ruin it. The Peloponnesian League demanded its repeal, Athens refused, and war broke out.

The war spread throughout the Greek world from Sicily to Asia Minor, lasting 27 years, and caused great destruction and loss of life. Athens lost and lost its empire, however this did not bring peace and prosperity – the Greek world was weakened but continued spradic wars. Sparta was temporarily dominant until defeated by Thebes.

To prevent it spilling over into its empire, Persia imposed the King’s Peace to mimise the damage. Macedon used this weakness and division to impose its dominance over Greece.