Once he succeeded in unifying the Mongol tribes, Genghis Khan and his tightly disciplined army conquered lands in northern China and Central Asia. Genghis Khan was also a far-sighted leader who developed policies that would aid in governing and in shaping the economies of the growing empire. Under his rule, Uyghur script was adapted for the writing of Mongolian, previously an unwritten language. A policy of religious tolerance was pursued to win over the newly conquered native populations. And foreigners were recruited for skilled administrative positions for which the Mongols lacked experience. The nomadic lifestyle of the Mongols had prevented the development of an artisan class, but Genghis, aware of the need for craftsmen, spared their lives when the Mongols conquered their lands, freed them from manual labor and taxes, and moved them to new areas.

When the Mongols established their huge empire, they continued their traditional support of merchants and craftsmen, which resulted in the greatest expansion of trade and tribute in Eurasian history. Traders, as well as diplomats and missionaries, traveled with few hindrances across Mongol domains, resulting in the first direct contacts between Europe and China. European missionaries and merchants, the most famous being Marco Polo, voyaged all the way to China, and Asian products—silks and spices—reached Europe, leading Europeans to seek a sea route to the East and its treasures.