Like most nomadic peoples of central Asia, the Mongols placed great store by their commercial relationships with neighboring peoples in sedentary agricultural societies. The steppelands of central Asian are too arid to permit extensive cultivation, and the nomadic way of life made it difficult for Mongols to maintain facilities for the manufacture of iron and other useful products. So the Mongols traded regularly with their agricultural neighbors, exchanging horses and animal products for grains and manufactured products. Since Mongols and other nomadic peoples knew their way around much of central Asia, they also often transported trade goods between settled societies. 

One of the Mongols' principal policies was to protect merchants and ambassadors who traveled through their realms, so long as they had proper documentation and authorization to do so. Thus, when Mongols gained control over a large portion of the Eurasian landmass, trade and travel became much safer than before. Overland trade surged during the age of the Mongol empires, with numerous merchants making their way from Italy to distant China. Marco Polo is only the best known of these Italian merchant travelers, who numbered into the hundreds, perhaps even the thousands during the thirteenth and early fourteenth centuries. As a result of their ventures, a well-traveled and relatively well-policed network of roads linked lands from the Mediterranean basin to China. 

While they mostly promoted increased trade, Mongol policies sometimes caused problems for merchants. Mongol rulers and princes frequently fought among themselves, which could lead to considerable disruption of trade networks. It's worth recalling, too, that the Mongols had little influence on seaborne trade, which was much larger in value and volume than the overland trade that passed through Mongol territories. After about the seventh century, seaborne trade surged in the Indian Ocean basin, which was the principal focus of trade in the eastern hemisphere both before and after the Mongol era.