These institutions, claiming supreme political power, directly performed their constitutional duties across executive, judicial, or legislative domains.

While political theory had not yet conceptualized the three-branch system common in modern republics, the functions existed in various forms, including the military, law courts, and economic regulation.

Groups of poleis with shared interests, such as building a strong military for offense or defense, might form alliances, like the Ionians who defended the Greek coast of Anatolia against incoming Iranians.

As the government of a league, a koinon encompassed functions like defense, diplomacy, economics, and religious practices among its member states.

Members of the alliance primarily contributed taxes, men, and equipment, rather than directly managing or issuing binding commands.