Between 1405 and 1433, Ming China sent out seven gigantic naval expeditions under the command of Zheng He the great eunuch admiral. These expeditions traveled along the Indian Ocean trade routes as far as Arabia and the coast of East Africa, but in 1433, the government suddenly called them off.
Scholars have wondered for centuries, "What prompted the end of the Treasure Fleet?"
In part, the sense of surprise and even bewilderment that the Ming government's decision elicits in western observers arises from a misunderstanding about the original purpose of Zheng He's voyages. Less than a century later, in 1497, the Portuguese explorer Vasco da Gama traveled to some of the same places from the west; he also called in at the ports of East Africa, and then headed to India, the reverse of the Chinese itinerary. Da Gama went in search of adventure and trade, so many westerners assume that the same motives inspired Zheng He's trips.
However, the Ming admiral and his treasure fleet were not engaged in a voyage of exploration, for one simple reason: the Chinese already knew about the ports and countries around the Indian Ocean. Indeed, both Zheng He's father and grandfather used the honorific hajji, an indication that they had performed their ritual pilgrimage to Mecca, on the Arabian Peninsula. Zheng He was not sailing off into the unknown.
Likewise, the Ming admiral was not sailing out in search of trade. For one thing, in the fifteenth century all the world coveted Chinese silks and porcelain; China had no need to seek out customers - China's customers came to them. For another, in the Confucian world order, merchants were considered to be among the lowliest members of society. Confucius saw merchants and other middlemen as parasites, profiting on the work of the farmers and artisans who actually produced trade goods. An imperial fleet would not sully itself with such a lowly matter as trade.
If not trade or new horizons, then, what was Zheng He seeking? The seven voyages of the Treasure Fleet were meant to display Chinese might to all the kingdoms and trade ports of the Indian Ocean world, and to bring back exotic toys and novelties for the emperor. In other words, Zheng He's enormous junks were intended to shock and awe other Asian principalities into offering tribute to the Ming.
So then, why did the Ming halt these voyages in 1433, and either burn the great fleet in its moorings or allow it to rot (depending upon the source)?
There were three principle reasons for this decision. First, the Yongle Emperor who sponsored Zheng He's first six voyages died in 1424. His son, the Hongle Emperor, was much more conservative and Confucianist in his thought, so he ordered the voyages stopped. (There was one last voyage under Yongle's grandson, Xuande, in 1430-33.)
In addition to the political motivation, the new emperor had a financial motivation. The treasure fleet voyages cost Ming China enormous amounts of money; since they were not trade excursions, the government recovered little of the cost. The Hongle Emperor inherited a treasury that was much emptier than it might have been, if not for his father's Indian Ocean adventures. China was self-sufficient; it didn't need anything from the Indian Ocean world, so why send out these huge fleets?
Finally, during the reigns of the Hongle and Xuande Emperors, Ming China faced a growing threat to its land borders in the west. The Mongols and other Central Asian peoples made increasingly bold raids on western China, forcing the Ming rulers to concentrate their attention and their resources on securing the country's inland borders.
For all of these reasons, Ming China stopped sending out the magnificent Treasure Fleet. However, it is still tempting to muse on the "what if" questions. What if the Chinese had continued to patrol the Indian Ocean? What if Vasco da Gama's four little Portuguese caravels had run into a stupendous fleet of more than 250 Chinese junks of various sizes, but all of them larger than the Portuguese flagship? How would world history have been different, if Ming China had ruled the waves in 1497-98?