Ionian League

The Ionian League (ancient Greek: Ἴωνες, Íōnes; κοινὸν Ἰώνων, koinón Iōnōn; or κοινὴ σύνοδος Ἰώνων, koinē sýnodos Iōnōn; Latin: commune consilium), also called the Panionic League, was a confederation formed at the end of the Meliac War in the mid-7th century BC comprising twelve Ionian cities (a dodecapolis, of which there were many others). These were listed by Herodotus as

After 650 BC Smyrna, an originally Aeolic city, was invited to diminish Aeolis and increase Ionia by joining the league, which it did.

One of our earliest historical sources, the Histories of Herodotus, and early inscriptions refer to the legally constituted body customarily translated by "league" as "the Ionians" in the special sense of the cities incorporated by it. One therefore reads of the cities, council or decisions "of the Ionians." Writers and documents of the Hellenistic Period explicitly use the term koinon ("common thing") or synodos ("synod") of the Ionians, and by anachronism apply it to the early league when they mention it.

The league was dissolved a few times and reconstituted a few times and in between its actual power varied. Under the Roman empire it was allowed to issue its own coinage under the name koinon Iōnōn on one side with the face of the emperor on the other.

The Meliac War was a final settlement between the ancient state of Caria and the Ionians who had been settlers on its land at the mouth of the Maeander for some centuries. Their last stronghold was the fortified settlement of Melia at the smaller peak of Dilek Daglari on the north slopes of Mycale, where the seat of their worship of Poseidon Heliconius was located. The fort was constructed in the early 7th century BC.

...
Wikipedia