For most of its history, China was not isolationist. For nearly 1,500 years up to the 14th century, China was a major trading nation. Maritime trade boomed during the Southern Song and Yuan dynasties from the early 12th century to late 14th century, making the Southern Song the wealthiest of all Chinese dynasties. 

So why did China’s last two dynasties, the Ming and Qing, turn their backs on openness and the wealth it brought? Why did they shift to a strict policy of isolation? 

People today have good reason to criticize the narrow-minded ruling class of the Ming and Qing. But among their reasons is that the enormous wealth generated from foreign trade also was the downfall of the powerful family, the world’s largest port city, and dynasties that underwrote it.