Trade, and in particular transactions carried out with partners across long distances, was hugely profitable, and cities located along established trade routes thrived. Such was the importance of market location, and the routes taken by merchants and their caravans, that central government often made it their business to control them. By dictating preferred routes governments could exert some control on who gained from the prosperity that booming trade brought. It allowed the government to select those who grew rich and those who were doomed to poverty.
