The member cities of the Ionian League met annually at the sanctuary of Poseidon Helikonios at the Panionion on the promontory of Mt. Mykale. Very little is left of the sanctuary now, though the foundation of a huge, 18 m Archaic altar has been detected. Also found at the site were a council chamber and a large cave, which must have played a role in the cult. The sanctuary probably never included a temple, yet it was an important symbol of political and cultural identity in the Archaic period. The priests were supplied by the city of Priene. Later the meeting place was moved for safety to a spot near Ephesos. Though this cult was almost certainly brought to Asia Minor when the Ionians migrated to their new homes around the tenth century, there is debate over its source, closely tied to the question of Ionian origins. One school of thought derives Poseidon Helikonios from the city of Helike in Achaia, often cited by ancient authors as a homeland of the Ionians. The Ionians of the Classical period seem to have believed this version, for in response to an oracle, they sent representatives to Helike to ask for sacred objects (aphidrumata) from the ancestral altars. The Achaians’ refusal to permit this privilege is said to have caused the famous earthquake and tidal wave that destroyed and engulfed Helike in 373.2 It is certain that an ancient cult of Poseidon was present at Helike, for Homer (II. 8.203-4) mentions offerings to the god from the people of Helike and Aigai. From a linguistic point of view, however, the word Helikonios is better derived from Helikon, the mountain in Boiotia. Though no Poseidon cult on Helikon is attested in historical times, the god had deep roots in Boiotia and such a cult may have largely faded from memory. In any case, Homer is also aware of the worship of Poseidon Helikonios, for he speaks (Il. 20.403-5) of the bellowing bulls sacrificed to “the Helikonian lord.” According to Strabo (8.7.2), some in antiquity took this as a reference to the sacrifices at the Panionia, where the participants read omens if the bull bellowed as it was struck down.3
On Delos, another Ionian religious center, a large sacrificial feast was held during the month Posideion, which fell during the stormy period of midwinter. Poseideia, or festivals of Poseidon, seem to have been a regular feature of this month in many Ionian cities, both in the islands and on the coast of Asia Minor. Poseidon’s epithets in these places vary, from Helikonios at Sinope to Asphalios (Steadfast) or Themeliouchos (of Foundations) on Delos and Phykios (of Seaweed) on Mykonos. Noel Robertson connects the winter festival to Poseidon’s function as a partner of Demeter in fructifying the fields; alternatively, the timing suggests a propitiation of the god who causes storms at the season when his anger is most evident.4
World History
