Panathenaea was an important annual festival of Pallas Athene that according to tradition dated from the time of the legendary king Theseus. From 566 BC Pisistratus, the Athenian aristocrat, arranged that every fourth year, when the festival would be known as the Greater Panathenaea, music and poetry competitions were included, together with games and the festival was extended by three or four days.
During annual Lesser Panathenaea there was a solemn procession to the Acropolis in thanksgiving to Athene for having saved the city, giving it victory over the ‘nation of Poseidon’. Ammianus Marcellinus recounts how the peplum, a richly embroidered robe of Minerva (the Roman equivalent of Athena) was carried in this procession, on which could be seen a representation of the war between the Athenians and the Atlantides. That this was a clear reference to the defeat of the Atlanteans is supported by Humboldt, Böckh, Donnelly[1179.91], Baldwin[0653.396] and Joseph. A minority view is that the victory celebrated by the procession was that which was fought against the Persians.
The fact that this ceremony was performed at least 138 years before Plato was even born would appear to demonstrate that he could not have invented the existence of Atlantis and in fact the celebratory procession was inaugurated long before the Persian Wars began.
The Parian Marble allows us to calculate the date of the first Panathenaea occurring in 1506/5 BC. If ‘the nation of Poseidon’ is not a reference to Atlantis, what does it refer to? One suggestion, perhaps more contentious, is that it is an illusion to the Sea Peoples.
The contest between Athena and Poseidon on the West pediment of the Acropolis is related to the later conflict between Erechtheus, an early king of Athens, and the Eleusinians under the leadership of Eumolpos. Keep in mind that Poseidon is the father of Eumolpos, dated by some to reigning around 1400 BC.
New research by Professor Efrosyni Boutsikas of the University of Kent has shown(a) that the start of the annual festival was signalled by the appearance of the Draco constellation over the Erechtheion on the Acropolis of Athens.