Emperor Zhu Di gave Zheng He two principle directives. The first required him to bring diplomats from all the world’s nations to China. The second directive required him to develop a worldwide system of maritime commerce. In order to achieve these royal mandates, Zheng He needed accurate maps.
Fortunately, the Admiral’s mission was aided by a substantial of world geography. Explorers in the previous Yuan Dynasty had already mapped many New Lands in America.
Evidence of Yuan Chinese exploration has reached the West mainly through the writings of the Venetian spy—Marco Polo.