Demeter is also known for founding the Eleusinian Mysteries. These were huge festivels held every five years. They were importaint events for many centuries. Yet, little is known of them as those attending were sworn to secrecy. The central tenant seems to have been that just as grain returns every spring after its harvest and wintery death, so too the human soul could be reborn after the death of the body.

Her age old feud with her brother, Poseidon, might serve to explain why the edge of the sea is barren of crops. The origin of this feud is vague.