Prince Zhu Di stormed the Chinese Imperial Palace and occupied its throne by force on a July day in 1402. As his first order of business, the new emperor executed hundreds of Confucian officials considered loyal to his sibling predecessor and thus launched a boom in trade.

Confucians had argued domestic agriculture alone must supply the Chinese economy. Now, private trade was permitted to Chinese citizens and port access granted to foreign merchants. “All within the four seas are one family,” Zhu Di said. “Let there be mutual trade at frontier barriers in order to supply the country’s needs and to encourage distant people to come.”

Unprecedented construction began on 1,700 oceangoing warships and support vessels. The largest of the fleet—so-called “treasure ships”—required nine masts and spanned 400-by-160 feet. Christopher Columbus’s Santa Maria would stretch only eighty-five feet. In fact, until World War I, the early-fifteenth-century Chinese armada was by far the most impressive the world had ever known. Its total crew numbered nearly 30,000. Their commander was eunuch Zheng He.

To be a eunuch was an invitation to power in fourteenth and fifteenth century China. Outside the Imperial Palace these men specialized in seafaring and trade. The most successful grew as rich as royalty. None would merit more than Zheng He.

Over the next three decades, the Treasure Fleet crossed the China Seas and India Ocean seven times, reaching the Persian Gulf, Africa, and, some claim, North America. From South Asia, ships carried home cardamom and cinnamon, ginger and turmeric, pepper and pearls. From present-day Sri Lanka and Malaysia came elephants, tigers, leopards, rare birds, and relics. In east Africa, Chinese silk and porcelain were traded for ivory, medicine, and precious stones.

 “Half the world was in China’s grasp, and with such a formidable navy the other half was easily within reach, had China wanted it,” writes Louise Levathes, author of When China Ruled the Seas. “China could have become the great colonial power, a hundred years before the great age of European exploration and expansion.”

China declined. Zhu Di considered himself all-powerful and his country—the Middle Kingdom—divinely chosen. Foreign goods were welcomed. But make the barbarians themselves his subjects? Never.

What happened next is an enduring lesson in the consequences when trade is driven by politics, not commerce.

Zhu Di died August 12, 1424. His son and successor sought Confucian counsel. “All voyages of the treasure ships are to be stopped,” he subsequently ordered. “All goods on the ships are to be turned over to the Department of Internal Affairs and stored.” Officials currently abroad on business were ordered back to the capital. Those selected for future voyages were ordered back to their home. Zheng He, now owner of a 70-room house, died at sea.

By 1450, repairs had ceased on the Treasure Fleet. Without reliable passage for visitors, the imperial tribute system shrank. Ambassadors gave way to smugglers. Fearing goods from outside powers could undermine authority, the government banned foreign trade. In 1500, to build a boat with three or more masts was a capital offense. Soon it was a crime simply to go to sea.

For almost 500 years, China all but abandoned world trade.

Today, we witness the second coming of the Treasure Fleet, though Chinese Communist Party leaders must share a far greater portion of the spoils than did Emperor Zhu Di.

Chinese exports account for half to two-thirds of all trade between Asia and Europe and North America. The country’s $17 billion China Ocean Shipping Company (COSCO) alone operates a 600-vessel merchant fleet whose annual traffic volume exceeds 300 million tons. Not to be outdone is the world’s largest containership, the Denmark-made Emma Maersk 3, which delivered a record 11,000 containers from China to Great Britain in its “S.S. Santa” Christmas voyage eighteen months ago with a crew that totaled just 13 sailors. Whether they realized it or not, all were descendants of admiral eunuch Zheng He. Wt