Panionion

Panionion was an Ionian sanctuary dedicated to Poseidon Helikonios dates bac to the IV/VIIIth century BC.. It was the centre of the Ionian dodecapolis and was a place of  the religious assembly of  Ionians accompanied by a great festival - Panionia. The sanctuary was on Prienian territory and under that city management¹Homer for the first time performed his epics in front of a larger audience ca. 700 BC².

1. https://www.academia.edu/50652400/Douglas_Frame_and_Homer_in_the_Panionion_What_is_left_of_Poseidon_Helikonios_His_Sanctuary_and_His_Bulls

References

1. ↑George E. Bean, Aegean Turkey, London Benn Ltd., 1966, p.216-218
2. ↑Gregory Nagy, Homer the Preclassic - http://chs.harvard.edu/CHS/article/display/3273