Helots

The subject population of Laconia and Messenia, bound to the land and to the Spartans collectively rather than owned as individual chattel. They farmed the allotments that paid each Spartan's mess contribution, which is what made a citizen body of full-time soldiers possible at all.

Thucydides states plainly that most Spartan institutions were designed with an eye to controlling them, and he records the episode that fixes the relationship. During the Peloponnesian War the Spartans invited helots who claimed the best war record to come forward for their freedom, selected around two thousand, crowned them and led them round the temples. Every one of them then disappeared, and no one knew how each had died.

Herodotus shows the same population in the field at Plataea, where he gives seven helots to each Spartiate, which if accurate implies a dependent population vastly outnumbering its masters. That imbalance is the standing fact of Spartan history.