What 464 BCE earthquake helped trigger a major helot revolt against ancient Sparta?

The 464 BCE Sparta earthquake helped trigger a major helot revolt against ancient Sparta.

The earthquake struck Laconia and devastated Sparta, killing many inhabitants. Ancient sources give dramatically different casualty figures, so modern historians treat the exact death toll cautiously. The disaster badly weakened the Spartan community at a moment when its dependent helot population was already central to the economy.

Helots in Messenia and Laconia rebelled soon afterward. The revolt became a serious military crisis, and Sparta requested assistance from other Greek states, including Athens. Spartan suspicion later led to the dismissal of the Athenian troops, worsening relations between the two powers.

The earthquake did not single-handedly cause the revolt; it created an opening for resistance. The long conflict is commonly called the Third Messenian War and showed how heavily Sparta depended on controlling the helots.