“Indeed, the map of medieval European “states” looks remarkably like a map of hunting-and-gathering cultures in Europe about five thousand years ago. The reason is that, unlike China or India, for example, Europe is not one large plain but a multitude of fertile valleys surrounded by mountains and dense forests, each often serving as the core area of an independent state. Wherever geographic barriers limit communications, cultural diversity always arises.”  –Rodney Stark, The Victory of Reason, 83.