In ancient Greece, a city-state, the political and social center of most larger Greek communities.
Membership in a polis as a citizen, participation in its cults and festivals, and the protection of its laws formed the basis of classical Greek civilization, which was marked by intense intercity rivalries and conflicts until the Hellenistic period.
Originally a citadel on a rock or hill, in classical times the polis consisted of a walled city with adjoining land, which could be extensive.