How trade may have worked in the ancient times is one of the most fascinating aspects about history for me. There is the Nebra sky disc[1], which is estimated to be 3500 years old. The gold seems to have come from Cornwall/England, the Copper came from Austria, and the disc itself may have been manufactured in Anatolia. This is not halfway around the world, but I wonder who did those trades. Was it individual adventurers or something like armies bringing the materials from one place to another? Was there an existing trade network in place?