The secret of this strange perversion of the natural life of man is to be found in the declaration of war annually made by the ephors upon the Helots. They could not follow it up by a campaign waged in regular fashion; for that would have been to destroy their own serfs. But they picked out young soldiers, and sent them about among the Helots, with instructions to strike down secretly all who seemed restless or over-ambitious. The chief centre of Helot disaffection, at least in the seventh and sixth centuries B.C., was on the far side of Mount Taygetus, in Messenia. There the yoke of serfdom chafed more than elsewhere, not least because those whose estates the Helots of Messenia tilled for one half the yield lived beyond the snow-capped ridge which shuts in that country on the east. The Messenians aspired to regain their lost independence. The Helots of the Eurotas Valley had no such ambition. They were, therefore, slower to revolt against injustice; but their aim, when an insurrection _did_ come, could be nothing less than the extermination of their masters, or at least an exchange of position with them. Moreover, their very proximity to the five villages which constituted the unwalled city of Sparta, and the very weight of their numbers made the Spartans live in ever-present fear of a massacre. Constant preparedness for war was, accordingly, a simple mandate of self-preservation. * * * * * The Spartans thought it unwise that any of their serf-tilled estates should lie in or outside the ring of Perioec land. It would not do to have fuses, so to speak, of Helots running through the wall to the outside world, or to have masses of Helots beyond the wall, exposed directly to foreign manipulation. Hence the formation of the Perioec ring set definite limits to the territory of Sparta. It could be enlarged in but one way--the widening of the ring by the reduction of more and more outlying states to the status of Perioecs. And it was in this way that the Spartan dominions were in fact enlarged in the seventh century B.C.[39]