On June 15, 1405, the third year of Yongle (1405), Ming Chengzu Zhu Di sent the Three Treasures eunuch Zheng He to lead a huge ocean-going fleet south to the West, starting the most spectacular and mysterious voyage in Chinese history. Zheng He's fleet was built at The Longjiang Dockyard in Nanjing, assembled at LiujiaGang in Taicang, Jiangsu Province, and officially anchored at Changle Taiping Port in Fuzhou, Fujian Province. Two years later, Zheng He's fleet returned to the Ming Dynasty with tribute emissaries from various countries, and the first Zheng He's voyage to the West was successfully concluded.
After completing its first ocean-going mission, Zheng He's fleet sailed to the Western Ocean in 1407, 1409, 1413, 1417, and 1421, as far as Java, India, the Horn of Africa, and the Strait of Hormuz, visiting more than 30 countries and regions along the way.
The "treasure ship" of Zheng He's fleet is a nine-masted flat-bottomed sailboat, which is 135.3 meters long and 56.7 meters wide. The smallest one is a five-masted flat-bottomed sailboat, which is 54.8 meters long and 20.7 meters wide. The entire fleet has about 27,000 sailors. It is worth mentioning that at the same time, the era of great navigation in Europe had not yet begun, and Zheng He's fleet, regardless of the size, technical level or number of ships, was beyond the reach of the Spanish Armada, which appeared 150 years later.
During Zhu Di's reign, he sent Zheng He to the West six times, and the number of voyages can be said to be very frequent. However, Zheng He's purpose of going to the West has become a mystery. To this day, it is still unclear why Zhu Di sent Zheng He to the West, so there have been various speculations.
There is a widely circulated theory that after the "Battle of Jingnan", Emperor Jianwen mysteriously disappeared, which became the most entangled thing in Zhu Di's heart. After all, his throne was taken from Emperor Jianwen, and as long as he was uncertain about the final outcome of Emperor Jianwen, his imperial throne could not be completely secured. Therefore, when he heard the news that Emperor Jianwen had fled to a foreign country, he sent Zheng He with a huge fleet to search. However, there is a "hard wound" in this statement: if Emperor Jianwen really did not die, he could have found a place to live in seclusion in The country at will, with ancient technical conditions, it is as difficult as finding a needle in a haystack in such a huge country, and there is no need to flee to a foreign country. Foreign people are not familiar with the place, and the language is not the same, and the risk of being discovered outside is even greater. Moreover, Zhu Di still sent Zheng He on a voyage until 1421, when Emperor Jianwen had long since ceased to pose no threat to him, so the claim to look for Emperor Jianwen was untenable.
In fact, the main purpose of Zhu Di's enthusiasm for sending Zheng He to the West was to promote the status of the Ming Dynasty as the center of the world to neighboring countries, expand the tributary system, and create the image of the co-lord of the world, so as to prove that he was the most suitable heir to the throne. In today's terms, Zheng He's purpose in going to the West was to export "soft power."
Throughout his life, Zhu Di suffered from the legitimacy of the throne, and many important decisions during his reign were actually to prove his ability and the legitimacy of obtaining the throne. In order to achieve this, he did not hesitate to send Zheng He with a huge fleet to and from China to Africa, spreading the ming dynasty's national prestige to all countries along the route. The two evaluations of Zhu Di's life and merits in the two sentences of "Wei De's quilt and four-way guest service" are indeed worthy of the name in the matter of Zheng He's voyage to the West.
Regrettably, Zheng He's voyage to the West could have opened up the Ming Dynasty's maritime hegemony, but the Ming Emperor did not realize the importance of this matter. Frequent ocean voyages did not grab territory or resources for the Ming Dynasty, but only brought back the abstract result of raising power for the Heavenly Dynasty.
In 1433, after Emperor Xuanzong of Ming completed Zheng He's last voyage to the West during the reign of Emperor Xuanzong Zhu Zhanji, the Ming Dynasty's maritime exploration operation was completely terminated. Since then, the navigation ability of the Ming Dynasty has been weakening day by day, so that in the middle of the Ming Dynasty, it has fallen to the point where even the coastal areas are difficult to deal with, and the maritime history of the Ming Dynasty has become a rusty hinge.
References: History of the Ming Dynasty, World Order in China