|This could easily be Tomb Kings or Tau.|
None other than H.G. Wells. Now to be fair, he based it on a military training simulation called Kriegspiel, but Wells created and published the first rule set that resembles the games we see today.
The Kotaku Article
The full version of Little Wars at Project Gutenberg
Of course, the mechanics and models have both become more sophisticated, but it's really amazing to see actually how little has changed. The terrain pictures are pretty amazing considering that it was really the first time someone did this for recreation, and the relatively mild chauvinism is pretty funny.
My favorite quote from the book is something he wrote about the much drier, more complicated Kriegspiel:
The British manufacturers who turn out these also make a smaller, cheaper type of man—the infantry about an inch high—which is better adapted to Kriegspiel purposes.