my current art project is themed around mythology so I’ve done a lot of research on a few different mythologies. One of the things I noticed most was that in each mythology the same character types pop up (e.g. Trickster), and generally there are three deities who appear as the main three and who the myths are often about.
There are similar themes in the various myths too (most commonly creation, love, betrayal and war) and in many places ideas cross over even though the myths come from different parts of the world and therefore different cultures. For example, a common idea is that they sun was drawn across the sky by a chariot usually steered by a God / Goddess and pulled by an animal sacred to the culture (e.g. Norse mythology = goats).
This made me think that maybe the myths originated from the same story and are, rather than being completely seperate stories, are different interpretations of the same story.