Helike

At the time of its destruction, Helike was the flourishing capital of the Achaean League, a confederation of city states, and revered throughout the ancient world as the cult centre for worship of Poseidon. The sacred grove of Poseidon was second only to the oracle at nearby Delphi in terms of sanctuary sites at that time, and in promoting a spirit of harmonious co-existence and collaboration with neighbouring states, Helike ensured that it largely remained uninvolved in the turbulent political upheaval around it. This state of political and social harmony, and the healthy economic growth that it encouraged, ended one winter’s night in 373 BC.

Numerous contemporary and later sources provide dramatic testimony to what happened to Helike and Bura that night. The Greek writer Pausanius, visiting the site of the devastation almost 500 years later, recounted how, ‘An earthquake struck the country and destroyed every single building, until the very foundations of the city were lost for all time.’

The accompanying seismic sea-wave ‘…flooded in far over the land and overwhelmed the city and its surroundings, and the swell of the sea so covered the sacred grove of Poseidon that nothing could be seen but the tops of the trees. A sudden tremor was sent by the god, and with the earthquake the sea ran back, dragging down Helike into the receding waters with every living person.’

After the disaster, whatever was left of Helike’s land was divided amongst its neighbours. The nearby city of Aegion assumed control of the Achaean League, and Helike went into political obscurity. A tradition sprang up amongst its Achaean neighbours that Helike had been punished by Poseidon for defiling the sanctuary, though it was perhaps more its unrivalled supremacy amongst the other city states that sealed its ultimate downfall.

Nevertheless, its removal from the political scene was mirrored by the physical removal of the city, believed by most ancient writers to now lie deep below the waters of the Corinthian gulf. Travellers like Strabo and Pausanius, searching out the city several centuries later, were shown only a few sunken ruins and accounts of a submerged bronze statue of Poseidon that snagged the nets of local fishermen.

http://www.bbc.co.uk/history/ancient/greeks/atlantis_01.shtml