Earlier this year, one of youse recommended that I read Lloyd Brown's The Story of Maps. First, thank you! I enjoyed it.
One of the things that really struck me was how closely held maps were for most of human history. "They were much more than an aid to navigation," Brown writes. "They were, in effect, the key to empire, the way to wealth. As such, their development in the early stages was shrouded in mystery, for the way to wealth is seldom shared. There is no doubt that the complete disappearance of all charts from the earliest period is due to their secret nature and to their importance as political and economic weapons of the highest order."
Reading that made me wonder if military historians should consider the invention of reliable maps as a revolution in military affairs, akin to the invention of the stirrup and the weaponization of gunpowder. If so, which nations benefited? First, it appears from reading Brown, were the Phoenicians -- though, he says, none of their maps has survived.