Zheng He led the (what was at the time) world's largest and most technologically advanced merchant class fleet under Chinese emperor Yongle. At the time, Chinese believe they were literally the center of the world. They had and still have an abundance of natural resources and had no need to go get any more from foreign lands. Therefore, the main point of this huge journey which lasted about 20-30 years was to establish strong economic and political relations with the Westerners (European nations) and to establish their military power too but that part uhh... didn't go that well lol. So Zheng He, as the genius navy admiral he was, led the largest trading fleet the world has ever seen to show the world Chinese capabilities, political and economic dominance, and to try to sort of 'civilize' what you would consider 3rd world nations of his time.