Wikipedia
Crypteia
The Crypteia or Krypteia ( Greek: κρυπτεία krupteía from κρυπτός kruptós, "hidden, secret things") was an ancient Spartan state institution involving young Spartan men. Its goal and nature are still a matter of discussion and debate among historians, but some scholars ( Wallon) consider the crypteia to be a kind of secret police and state security force organized by the ruling classes of Sparta whose purpose was to terrorize the servile helot population. Others ( Köchly, Wachsmuth) believe it to be a form of military training, similar to the Athenian ephebia.