I was reading The Apology by Plato and in a court trial, Socrates notes that trying to argue with his public accusers that aren't there is kind of like fighting with shadows. Somehow my brain made the connection that ancient Greeks had boxing. I began wondering how far back shadowboxing as a popular training practice goes. Its kind of a problematic question, as boxing doesn't enjoy an unbroken history from the time of Ancient Greece to the modern day, but I'll bet there's some history there. It would also be interesting to hear any accounts of shadowboxing history from muay thai or panatukan. I would guess that its something you see in every era of boxing.
Litlle known fact
I am 3-1-1 in shadowboxing
It's impossible to have a shadowboxing record since it isn't a fight, but to be on topic I suppose it would make sense that older cultures with boxing-esque (or non boxing-esque, for that matter) combat sports would use a form of it as practice.