The helots were used as unskilled serfs, tilling Spartan land. Those who did not emigrate were reduced socially to helots, or serfs. Spartans instead relied on slaves named helots for civilian jobs such as farming. Athens also agreed to come to Sparta's aid if the Helots revolted. This time, the Athenians set their sights on the helots of Laconia. Also present were the 400 Thebans and probably the helots who had accompanied the Spartans. Besides, the rations mentioned by Thucydides for the Helots on Sphacteria are close to normal. Consequently, fear seems to be an important factor governing relations between Spartans and Helots. Their aim was probably to instigate a revolt of the Messanian helots against Sparta. Sparta had a special type of slaves called "helots". Spartan citizens used helots, a dependent group collectively owned by the state. Relations between the helots and their Spartan masters were sometimes strained. The earthquake sparked a revolt of the helots, the slave class of Spartan society. Finally, some authors make responsibility for the uprising with the helots of Laconia. There was a ratio of 7 or 8 helots to every Spartan citizen.