Excerpts from Books and Wikipedia
"In the mid-14th century, plague raged across China, and Mongol rule was collapsing. . . . From the New World would later come potatoes, maize, peanuts, and tobacco, which could be grown in areas where rice could not. With prosperity and population increases, the job market improved, and China began producing larger amounts of products . . . Under the Ming, China became a true sea power. Then, for reasons not entirely clear, the Ming retreated from maritime activity. . . . Chinese commerce was stimulated by the flow of silver from the New World . . ." [National Geographic Almanac, p. 168-71] "Eventually the court would have 70,000 eunuchs." [Fairbank: China, p. 128-41] "Apart from the costs and other disincentives involved, therefore, a key element in China's retreat was the sheer conservatism of the Confucian bureaucracy--a conservatism heightened in the Ming period by resentment at the changes earlier forced upon them by the Mongols. In this 'Restoration' atmosphere, the all-important officialdom was concerned to preserve and recapture the past, not to create a brighter future based upon overseas expansion and commerce." [Kennedy: Great Powers, p. 7-8]