system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How was it possible to orally record mythologies and other literature thousands of years ago, without the use of written scripts, and still have the almost similar elements in various versions?
gpt
People's memories were a lot better before writing became commonplace.

Also, part of what makes something great poetry is that it *is* easy to remember.  "Poetry" that fails at this is, in a pre-literate society, never going to become popular in the first place, and poets who don't put an effort into it are going to find themselves out of a job.