The sacred rites of Demeter were performed in Eleusis in Ancient Greece beginning as far back as the 15th Century BCE, according to some sources.
When she is discovered to be a Goddess by the queen Metaneira after trying in vain to make Demophon immortal, she instructed the Eluesinians to build a temple for her.
[3] While at first the cult of Demeter remained small, it eventually grew quite large after Eleusis was incorporated into Athens during the Archaic period.
After some time, it drew crowds from thousands of people around Greece, and even leaders like Peisistratos, Pericles, Hadrian, and Antoninus Pius all came to erect monuments at Eleusis.
[4] In addition, the rites became so important to the Greeks that until Roman rule, the Sacred Way remained the only road in central Greece.
[7] Finally, on the 13th of Boedromion, priestesses of Demeter and Persephone carried baskets of Sacred Objects, called the hiera, from Eleusis to Athens in preparation for the procession and the rites of the Greater Mysteries.
[8] On the first day of the celebration, initiates dressed in simple attire gathered with their teachers, as well as a large crowd, in the Agora in front of the Stoa Poikile for the proclamation by the hierophant of Demeter.
On the fourth day, the cults of Asclepius, God of Medicine, and Hygieia, Goddess of Health, joined the celebration in Athens.
On this day, thousands of celebrants, led by the initiates and priests in front of them joined the Grand Procession beginning at the Sacred Gate.
[11] They would then stop at the Cephissus River where kids in the procession would offer a lock of hair before moving on to the temple precinct at Daphni and the sanctuary of Aphrodite nearby.