See Also Extra Credits on the Bronze Age Collapse:
https://www.youtube.com/watch?v=KkMP328eU5Q
https://www.youtube.com/watch?v=QMBM1qazAXE
https://www.youtube.com/watch?v=y-8uv4D7cOE < This one in particular
https://www.youtube.com/watch?v=KkMP328eU5Q
https://www.youtube.com/watch?v=QMBM1qazAXE
https://www.youtube.com/watch?v=y-8uv4D7cOE < This one in particular
Also, I think it's a mistake to assume people were dummies back then. If you think about it, humans have accomplished amazing things over the millenia, and some of those discoveries are still important today (every cryptography book still covers Euclid's GCD in its early chapters). Dismissing them as barely literate IMO is ignoring the important lessons that history has for us.