The perioeci, or perioikoi, were the members of an autonomous group of free but non-citizen inhabitants of Sparta. Concentrated in the beach and highland areas of Laconia, the name derives from περί / perí, "around," and οἶκος / oikos, "dwelling, house." They were the only people allowed to travel to other cities, which the Spartans were not, unless given permission.
There was a tradition in ancient Greece which held that the perioeci were former Achaeans who had been invaded by the Dorians - where the Achaeans of the plains became helots, Acheans of the mountains became perioeci. There was another theory that they were settled from Lacedaemon, thus being analogous to the Roman colonies. However, Messenia was one exception to this theory, and it became difficult over time to believe that Sparta could found hundreds of perioecid villages.
Under the rule of Sparta, the perioeci belonged to the Lacedaemonian State, subject to the suzerainty of Sparta but not Spartan citizens. If their free status was not the object of controversy, the situation was unclear concerning the precise nature of their subject status within Sparta versus the status of allied cities and the strangers. In the same way, their political and social organization was quite poor.
Their territory, the Perioikis (Περίοικις), formed part of their territory within Sparta itself. Their villages were described as poleis by Herodotus (VII, 234), Xenophon (Hellenica, VI, 5, 21) and Thucydides (V, 54, 1). It can be noted that their poleis acted as a sort of buffer around Sparta, shielding it from outside influence. They were permitted to have some contact with outsiders and to trade.
The perioeci had the rights to own lands, and belonged to the civic army the same title as equals: they were hoplites in the army and epibastes in the navy. They could not participate in any political decisions and could not marry Spartan men or women.