The Phocians, however, would not have formed an autonomous political entity, had they not faced the political pressure of the Thessalians, who managed to conquer Phocis in 595 B.C., during the First Sacred War. The reason was the fame and power that the sanctuary of Delphi (controlled, so far by the inhbitants of Krissa) had acquired meanwhile. The control of the sanctuary would influence the political and military decisions which affected not only Greece but also all the Greek communities in the then known world. Under Thessalian tutellage, the Phocians united and finally created a federal state, the Phocian League, with a common bouleuterion (To Phokikon) and common coinage. All the cities had equal participation in the confederation.
There were 42 cities in total, of which the most important were 22: Lilaea, Erochos, Charadra, Elateia, Tithorea, Amphikleia, Drymaea or Drymon or Drymos, Teuthronion, Tritaea, Pedieia, Ledon, Avae, Yambolis (to the east, close to Boeotian Kephisus), Daulis, Panopeus, Phlygonio (in Elikon), Steiris, Ambrossos (on the south slopes of Parnassus, Krissa, Echedameia, Anemoleia (towards the region of the Ozolian Locrians) and the coastal cities Kirrha, Antikyra (possibly identified with the homeric Kyparissos), Medeon and Voulis.
Furthermore, the towns Aeolidon Polis, Apollonias, Evenos (possibly close to Elateia), Eranos (possibly modern Kyparissi), Kirphis (close to Delphi), Kleonae (close to Yambolis), Lykoreia (high up on Mt. Parnassus), Marathos (close to the monastery of Hosios Loukas in Beoeotia) Oghis, Trachis (close to Chaeroneia), Yapoia and Phokikon (south of Dauleia) are mentioned in ancient sources.
Elateia was the capital of the Phocian League. Coins were initially minted in Elateia, Lilaea, Antikyra and Ledon. Some of the aforementioned cities nowadays belong to Boeotia and some in Phokis, whereas Elateia, capital of the League, and Amphikleia, are situated in Phthiotis.