In the second year of Yongle, Emperor Zhu Di wanted to open the sea ban and revive the shipping route. Unexpectedly, the first batch of envoys to the South Seas did not return by the due date. When the envoys disappeared, rumors began to spread, so Zhu Di sent Zheng He, an official eunuch, to the West China Sea to find out the truth about the envoys' disappearance, and to build up a good relationship with all the countries along the way to revive the sea trade.