Tsunamis gave rise to temple to Poseidon

The site of an ancient sanctuary on the west coast of the Peloponnese peninsula. Image: Birgitta Eder / Athens Branch of the AAI

The site of a temple to Poseidon - the olympian who presided over the sea, storms and tsunamis in ancient Greek myth and belief - has been found on the Peloponnese peninsula.

The ancient Greek historian Strabo referred to the presence of an important shrine in the region some 2,000 years ago. Remains of an archaic temple have now been uncovered at Kleidi, near Samikon, which is presumed to have once formed part of the sanctuary of Poseidon.

Geophysicist Dr Dennis Wilken of Kiel University found traces of structures at a site at the foot of a group of hills in autumn 2021. After initial excavations under the supervision of Dr Birgitta Eder the following autumn, they proved to be the foundations of an ancient temple that could be the long-sought temple to Poseidon.

"The location of this uncovered sacred site matches the details provided by Strabo in his writings," said Eder, who is working for the Austrian Archaeological Institute (AAI), in collaboration with colleagues from two German institutions - Johannes Gutenberg University Mainz (JGU) and Kiel University, along with the Ephorate of Antiquities of Elis, Greece.

The team unearthed the remains of an early temple-like structure that was located within the Poseidon sanctuary site and was quite possibly dedicated to the deity himself. A fragment of a marble perirrhanterion, a water basin used for ceremonial washing in sanctuaries, was also recovered, and provides evidence for dating the large building to the Greek archaic period.

Part of a ceremonial water basin was found at the site. Image: Birgitta Eder / Athens Branch of the AAI.

The researchers say it is possible this location was selected as the site of the Poseidon temple because of the extreme natural phenomena occurring locally, given Poseidon's cult title - 'Earthshaker' - and his responsibility for earthquakes and tsunamis. In ancient Greece, it was also believed that Poseidon could create springs with a strike of his trident, the prongs of which symbolise the three properties of water - liquidity, fecundity and potability.

Roman scholar Maurus Servius Honoratus believed the three prongs represented "three kinds of water: seas, streams and rivers" to followers of Poseidon.

Evidence has been found that the region was repeatedly afflicted by tsunamis in both the prehistoric and historic periods, most recently in the sixth and fourteenth centuries. This tallies with surviving reports of known tsunamis that occurred in the years 551 and 1303.

"The results of our investigations to date indicate that the waves of the open Ionian Sea actually washed up directly against the group of hills until the fifth millennium BCE. Thereafter, on the side facing the sea, an extensive beach barrier system developed in which several lagoons were isolated from the sea," said Professor Andreas Vött of JGU in Germany.

"The elevated situation provided by the hills would have been of fundamental importance in antiquity as it would have made it possible to move on dry land along the coast to the north and to the south."

Excavations revealed foundations believed to be remains of a temple to Poseidon. Image: Dr Birgitta Eder / Athens Branch of the AAI

The natural hazard research and geoarchaeology team at JGU studies the processes of coastal change and extreme wave events and have been examining the development of the coast of Greece over the last 11,600 years. Their work involves identifying sea level changes and the corresponding coastal changes.

The detection of extreme wave events of the past, which in the Mediterranean mainly take the form of tsunamis, is a core feature of their investigations, along with analysis of their impact on coasts and the communities living there.