A fine alternate-history illustration

This fine Richard Hess cover for The Oxford Book of Military Anecdotes (Oxford UP, 1985) is a work of alternate history, unlike the book it was commissioned to wrap around. 

I wonder whether Hess read Philip Jose Farmer's Riverworld series -- though in Farmer's novels, all the world's most famous military leaders didn't wake up on the same patch of riverbank, fortunately.  Moreover, most of Hess' characters are clearly older than 25.