Any of the native peoples of Laconia and Messenia conquered and controlled by Sparta. They were state-owned serfs or slaves who worked the land to feed and clothe the Spartan population, whom they vastly outnumbered. Their masters could not free them or sell them. The Spartans lived in constant fear of a helot revolt and annually declared war on them to legally keep them in place by force. During wartime, helots attended their masters on campaigns, serving as troops and as rowers in the fleet. The Messenian helots were liberated c. 370 BC, those in Laconia not until the 2nd century BC.