Editing Telesterion (section)

===Religious use===
[[File:Plan of Eleusis, 081170.jpg|alt=Map of the Eleusis site|thumb|Plan of [[Eleusis]]|231x231px]]The Athenians used several calendars, each for different purposes. The festival of Eleusinia was celebrated each year in Eleusis and Athens for nine days from the 15th to the 23rd of the month of [[Attic calendar|Boedromion]] (in September or October of the [[Gregorian calendar]]); because the festival calendar had 12 [[Lunar month|lunar months]], the celebrations were not strictly calibrated to a year of 365 days. During the festival, Athens was crowded with visitors.<ref name="Antiq" />

At the climax of the ceremonies at Eleusis, the initiates entered the Telesterion where they were shown the sacred relics of [[Demeter]] and the priestesses revealed their visions of the holy night (probably a fire that represented the possibility of [[Afterlife|life after death]]). This was the most secretive part of the Mysteries and those who had been initiated were forbidden to ever speak of the events that took place in the Telesterion.<ref name=":1" />[[File:Terracotta votive plaque from Eleusis, 450 BC, NAMA, 190873.jpg|alt=Plaque showing people from Eleusis|thumb|[[Terracotta]] Votive Plaque From [[Eleusis]], 450 BCE (NAMA)|258x258px]]

The origin of the ritual of the [[Eleusinian Mysteries|Eleusinia]] is from the myth of [[Persephone]] being abducted by [[Hades]] to the underworld, while her mother [[Demeter]] frantically seeks her in the mortal world. After she learns that [[Zeus]] allowed the kidnapping to happen, she turns herself into an old women and wanders the world until she reaches Eleusis, where she is taken in by the King's daughters. She is overcome with grief, but is given Queen Metanira's latest born child, Demophoon to nurse. He grows more than any other child, but his mother is afraid when he is put over a flame before he can be made fully immortal. Demeter gets angry, and tells her that since she robbed her son of immortality and angered her, the people of Eleusis must create a temple to her where they would do things to gain back her favor. Even after Demeter got her daughter back from Hades for part of the year, the Eleusinian Mysteries continued.<ref>{{Cite web|title=Harry Thurston Peck, Harpers Dictionary of Classical Antiquities (1898), Eleusinia|url=http://www.perseus.tufts.edu/hopper/text?doc=Perseus:text:1999.04.0062:entry=eleusinia-harpers&highlight=telesterion|access-date=2021-11-15|website=www.perseus.tufts.edu}}</ref>

It was said in myth that [[Heracles|Herakles]] partook in the Eleusian Mysteries as part of the [[Labours of Hercules]]' twelfth labor in which he captured [[Cerberus]], and during which he saw visions of both Persephone and Demeter.<ref name=":4" />

Some temple use ceased during the [[persecution of pagans in the late Roman Empire]], when all non-Christian sanctuaries were ordered closed by laws initiated by the Christian emperors. However, it was not until the anti-pagan decree of Theodosius in around 390 CE that there was an end to all religious use of the temple.<ref name=":2" />