It was held annually, mostly around the time that seeds were sown in late autumn – though in some places it was associated with the harvest instead – and celebrated human and agricultural fertility.
[2] The best evidence for the Thesmophoria concern its practice in Athens, but there is also information from elsewhere in the Greek world, including Arcadia,[3] Sicily and Eretria.
[4] The festival was dedicated to Demeter and her daughter Persephone[5] and was celebrated in order to promote fertility, both human and agricultural.
[4] This corresponds to late October in the Gregorian calendar, and was the time of the Greek year when seeds were sown.
[9] In other places the festival lasted for longer – in Syracuse, Sicily, the Thesmophoria was a ten-day long event.
Herodotus mentions the Thesmophoria in the second book of 'the Histories' and compares it to a similar Egyptian mystery ritual.
However, he claims that the rite was introduced to the Pelasgian women in Greece by the daughters of Danaus, a mythical king of Libya.
Herodotus further claims that knowledge of the Thesmophoria was nearly lost following ethnic cleansing of the Pelasgians by the Dorians in the Peloponnese.
[15] Some time later, the rotten remains of these sacrifices were retrieved from the pits by "bailers" – women who were required to spend three days in a state of ritual purity before descending into the megara.