The Qing takeover was done by the multi-ethnic Han Banners, Mongol Banners, and Manchu Banners which made up the Qing military. In 1644, the Ming was invaded by an army that had only a fraction of Manchus, the invading army was multi-ethnic, with Han Banners, Mongols Banners, and Manchu Banners.

On April 24, 1644, Beijing fell to a rebel army led by Li Zicheng, a former minor Ming official who became the leader of the peasant revolt and then proclaimed the Shun dynasty. The last Ming emperor, the Chongzhen Emperor, hanged himself on a tree in the imperial garden outside the Forbidden City.

Combined with crop failure, floods, and the Great Plague, the dynasty collapsed before the rebel leader Li Zicheng, who was himself defeated shortly afterward by the Manchu-led Eight Banner armies who founded the Qing dynasty.

The fall of the Ming dynasty was caused by a combination of factors, including an economic disaster due to lack of silver, a series of natural disasters, peasant uprisings, and finally attacks by the Manchu people.

In addition to political motivation, the new emperor had 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. For all of these reasons, Ming China stopped sending out the magnificent Treasure Fleet.

During the 1930s, the combination of the Great Depression and the memory of tragic losses in World War I contributed to pushing American public opinion and policy toward isolationism. Isolationists advocated non-involvement in European and Asian conflicts and non-entanglement in international politics.

What Is a Closed Economy? A closed economy is one that has no trading activity with outside economies. The closed economy is therefore entirely self-sufficient, which means no imports come into the country and no exports leave the country.