At the beginning of the chapter the author states, “travelers and traders seldom owned much land or wielded political power. socially isolated (sometime by law) and secretive because any talk about markets, products, routes, and travel conditions could their competitors, they nevertheless contributed more to drawing the world together than did all but a few kings and emperors.” if this is the case, then what role did trade play in their various societies between 300 bce and 1100 ce?