sympoliteia

thumb|Map illustrating the various alliances of the Peloponnesian Wars

A sympoliteia (), anglicized as sympolity, was a type of treaty for political organization in ancient Greece. By the time of the Hellenistic period, it occurred in two forms. In mainland Greece, the term was often used for a federal state consisting of individual poleis (city-states) with shared political institutions and citizenship. Examples of this are the Achaean League and the Aetolian League. The term was also used for the political merger of two or more neighboring poleis. This could eventually, but not necessarily, lead to the disappearance of one of the participating poleis. This second form was especially common in Hellenistic Asia Minor.