The Rheitoi lakes were the traditional border between Eleusis and Athens. They were famous for the delicious eels that lived in their waters. The animals belonged to Demeter and Persephone, and only the priests of the two goddesses could eat them. On the opposite shore was the mythical kingdom of Crocon, who was considered the husband of Saesara, daughter of King Celeus of Eleusis. The domain was imaginary, but those who belonged to the genos of the Krokonidai did not miss the opportunity to display their aristocratic mythological roots by describing Crocon as the son of Triptolemus (a theory that met with strong reaction from members of the Koironidai, who claimed the same priestly offices as the Krokonidai and never missed an opportunity to argue that Crocon was not the son of Triptolemus but a close relative).

An undisputed privilege was the right of the descendants of Crocon to tie a woollen saffron-coloured ribbon (kroke) around the right hand and the left leg of each initiate who passed through Rheitoi during the procession on the 19th of Boedromion. The meaning of the kroke is not clear. The ribbon might have been used as a protection against menacing spirits and the evil eye. On a practical level, too, the kroke allowed the mystai to rest for a while and filled some hours of the day so that the arrival in Eleusis would take place at sunset.