Our oldest stories are myths, usually creation stories of some sort. Myths relied on natural symbols to express ideas difficult to prove. As an example, found in the Hebrew book of Genesis is the story of the garden of Eden. It is borrowed from the earlier mesopotamian Gilgamesh Epic, in which a man and his wife are the only two people on earth, and they live in a paradise of delight at the mouth of two rivers, the Tigris and the Euphrates. Genesis incorporates this myth in a modified form to present its own vision that man is doomed to death as a result of his rebellion against God.
Myths are stories which interpret the universe, and infuse it with personal meaning.
That is the purpose of myth. To go one step further, the purpose of religious liturgy is to allow people to share a common story by actually reliving it together. Religions develop a liturgy for this purpose, to relive the religious story in order to keep the memory of it alive in the present. What effect, is up to the historian. It depends on what the historian wants you to experience.