Oral traditions, including fables and mythology, along with their mnemonic structures of repetition, reference, allusion, rhyme, meter, character, plot, etc., were early stores of knowledge and wisdom. Education for youth, knowledge of when to plant, how to spin, what natural resources (plants, animals, trees, minerals) were valued, skills in hunting, sailing, fishing, and war.

These were finally recorded in written form around the 6th century or so in much of Europe and Asia. Subsequent scholars (Idries Shaw who's 1970's World Tales is a collection of such stories being an exemplar) has found that the same stories occur again and again across cultures.

The etymologies of Zeus and Jupiter (*dyeu-peter- "Zeus Pater", literally Sky Father) are from Sanskrit, and similar / related names are shared and found across Eurasia.

https://idriesshahfoundation.org/books/world-tales/

https://www.etymonline.com/word/Jupiter