I love this sort of narrative. For example, the story of the stirrup is amazing to me. Before the stirrup was in common use, a knight in armor could not get onto a horse by himself and if he was knocked off the horse, he couldn't get back on without his man to help him. The stirrup and saddle gave a rider much better control of his mount. It is said to have orginated in China and spread west by nomadic tribes and armies. It came into use in Europe in the middle ages and facilitated the Crusades. Some say it was a game-changing invention like the printing press and the wheel. The only good thing we can say about the Crusades is that it led to an exchange of culltures and also gave second, third, etc sons of kings something to do. When they came home they became the Knights Templar who, blah, blah, woof, woof. And so on and on.