Conversation so far:
How did Lead Belly come up with his piano-sounding technique?
Lead Belly used down-tuning, with notes shifting as strings wore, as it was a common technique before the development of truss rods.
How old was Lead Belly when he came up with his down-tuning technique?

Question: Was the technique influenced by someone or something in his life?
Self-contained rewrite: Was the piano-sounding technique influenced by someone or something in Lead Belly's life?