The Sparta earthquake of 464 BCE destroys much of Sparta, a city-state of ancient Greece.
Historical sources suggest that the death toll may have been as high as 20,000, although modern scholars suggest that this figure is likely an exaggeration.
The earthquake sparks a revolt of the helots, the enslaved class of Spartan society.
Events surrounding this revolt lead to an increase in tension between Sparta and their rival Athens and the cancellation of a treaty between them.
After the troops of a relief expedition dispatched by conservative Athenians are sent back with cold thanks, Athenian democracy itself falls into the hands of reformers and moves toward a more populist and anti-Spartan policy.
Therefore this earthquake is cited by historical sources as one of the key events that led up to the First Peloponnesian War.
