There, advancing soundlessly by night, as every graduate of the agoge had been trained to do, they would be expected to prove themselves as killers. Of all men, it was said, only the Spartans denied that homicide was necessarily a crime; for it was, in their opinion, perfectly legitimate to cull their slaves. Nervous lest the gods be provoked against them, however, the Spartans would proclaim each year a state of war against the helots, a manoeuvre of typically murderous circumspection, calculated to spare the Crypteia any risk of blood pollution.