Excellent question! I am working my way up to reading this book: Mapping the Chinese and Islamic worlds Cross Cultural Exchange in Pre Modern Asisa I am still reading this book however and have made a few articles relating to it as it brings up so many more research questions as yours: A Splendid Exchange: How Trade Shaped the World I find it funny to learn about our ancestors trying out fire for food and for cooking rocks! Can you imagine? Took some time to figure out copper and it couples with the club. Hey that tribe over there has club technology. I know how about some light weight metal. Boys, cook up some rocks and let's invent Armour and helmets with leather and bronze. There that's the head banger warrior spirit. You can follow the trade routes from the metal mining camps and indeed this shaped how civilizations evolved. Hwa rang Jesuits can you get for Olympian gold?