If we go back in history what is the earliest form of communication that would have been scalable?
I could think of "writing" and "Paintings"
Paintings suffer from a problem which is context, unlike writing.
When writing as a communication medium began, asynchronously lot of people would have access to knowledge an older group of people experienced.
The below one in tamil was written some 2000 years ago by Thiruvalluvar with 7 words. Its meaning can change anyone who reads it.
தெய்வத்தான் ஆகா தெனினும் முயற்சிதன்
மெய்வருத்தக் கூலி தரும்.
Even though God be against it, Effort is bound to pay the wages of labour.