Before the printing press, access to "knowledge" was through designated privileged members of society -- priests, etc.
Few (if any) "laypeople" did their own research, as you and I understand it today.
Few (if any) "laypeople" did their own research, as you and I understand it today.
And even this scenario assumes a working postal system, availability of paper and pen. But if you didn't have those, you may not have heard of Greek to even ask the question.