This reminds me of Civilization II. My hallmark for a good game was getting railroads before Christ. You have to set it to a pretty easy level for that to happen, but it was a cheap thrill. I'm not surprised by this kind of technology. You'd have a foundational genius in his shop and he'd pass his skills onto apprentices. One of them might also be a genius of the same caliber and would add his skill to his master's skill, producing devices like this along the way. But, what if he died young, didn't have worthy apprentices, or his whole shop got killed when a city was sacked? Poof. It's all gone. Without print and the institutions to preserve printed materials, knowledge would get lost, especially because craftsmen often considered their knowledge secret to be passed only to the worthy. T

'Course, I am not a real scholar so I may be full it.