If Kristof's supposition is correct, then this remote African outpost retains an echo of one of history's most astonishing episodes of maritime exploration.

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In the 15th century, Zheng He, seen here with one of his massive ships in a painting at a temple shrine in Malaysia, led seven enormous seafaring expeditions. © Chris Hellier/Corbis

An Oriental armada

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Six centuries ago, a mighty armada of Chinese ships crossed the China Sea, then ventured west to Ceylon, Arabia, and East Africa. The fleet consisted of giant nine-masted junks, escorted by dozens of supply ships, water tankers, transports for cavalry horses, and patrol boats. The armada's crew totaled more than 27,000 sailors and soldiers. The largest of the junks were said to be over 400 feet long and 150 feet wide. (The Santa Maria, Columbus's largest ship, was a mere 90 by 30 feet and his crew numbered only 90.)

Loaded with Chinese silk, porcelain, and lacquerware, the junks visited ports around the Indian Ocean. Here, Arab and African merchants exchanged the spices, ivory, medicines, rare woods, and pearls so eagerly sought by the Chinese imperial court.

Seven times, from 1405 to 1433, the treasure fleets set off for the unknown. These seven great expeditions brought a vast web of trading links—from Taiwan to the Persian Gulf—under Chinese imperial control. This took place half a century before the first Europeans, rounding the tip of Africa in frail Portuguese caravels, "discovered" the Indian Ocean.

Related The Sacrificial Ceremony The Lost Inca Empire Ice Mummies of the Inca Columbus's ships Santa Maria (foreground) and Nina would have appeared pint-sized next to Zheng He's largest vessels. © Dorling_Kindersley/iStockphoto

With unrivaled nautical technology and countless other inventions to their credit, the Chinese were now poised to expand their influence beyond India and Africa. Here was one of history's great turning points. Had the Chinese emperors continued their huge investments in the treasure fleets, there is little reason why they, rather than the Portuguese, Spanish, Dutch and British, should not have colonized the world. Yet less than a century later, all overseas trade was banned, and it became a capital offense to set sail from China in a multi-masted ship. What explains this astonishing reversal of policy?

Roots of Chinese seapower

The first Chinese oceangoing trade ships were built far back in the Song dynasty (c. 960-1270). But it was the subsequent Mongol emperors (the Yuan dynasty of c. 1271-1368) who commissioned the first imperial treasure fleets and founded trading posts in Sumatra, Ceylon, and southern India. When Marco Polo made his famous journey to the Mongol court, he described four-masted junks with 60 individual cabins for merchants, watertight bulkheads, and crews of up to 300.

Despite the strength and prosperity that marked their empire, Ming emperors deliberately chose not to try to colonize lands beyond the Middle Kingdom. Why? Pierre Corrade

When the Han Chinese overthrew the Mongols and founded the Ming dynasty in the later 14th century, they took over the fleet and an already extensive trade network. The enterprising spirit of the Ming era reached a climax following the rebellion of the warrior prince Zhu Di, who usurped the throne in 1402. Disapproved of by the Confucian "establishment," Zhu Di put his trust in the worldly eunuchs who had always sought their fortunes in commerce. During his revolt, Zhu Di's right-hand man had been the Muslim eunuch Zheng He, whom he now appointed to command the treasure fleet.

If accurate, these dimensions would signal the biggest wooden ships ever built.

At the start of the first of Zheng He's epic voyages in 1403, it is said that 317 ships gathered in the port of Nanjing. As sociologist Janet Abu-Lughod notes, "The impressive show of force that paraded around the Indian Ocean during the first three decades of the 15th century was intended to signal the 'barbarian nations' that China had reassumed her rightful place in the firmament of nations—had once again become the 'Middle Kingdom' of the world."

Treasure junks: fact or fiction?

The Ming account of the voyages that followed strains credulity: "The ships which sail the Southern Sea are like houses. When their sails are spread they are like great clouds in the sky." Were the reported dimensions of the biggest galleons—over 400 feet long by 150 wide—gross exaggerations? If accurate, these dimensions would signal the biggest wooden ships ever built. Only the mightiest wooden warships of the Victorian age approached these lengths, and several of these vessels suffered from structural problems that required extensive internal iron supports to hold the hull together. No such structures are reported in the Chinese sources.

Zheng He's ships, as depicted in a Chinese woodblock print thought to date to the early 17th century Courtesy of Instructional Resources Corporation, www.historypictures.com

However, in 1962, the rudderpost of a treasure ship was excavated in the ruins of one of the Ming boatyards in Nanjing. This timber was no less than 36 feet long. Reverse engineering using the proportions typical of a traditional junk indicated a hull length of around 500 feet.

Unfortunately, other archeological traces of this "golden age" of Chinese seafaring remain elusive. One of the most intensively studied wrecks, found at Quanzhou in 1973, dates from the earlier Song period; this substantial double-masted ship probably sank sometime in the 1270s. Its V-shaped hull is framed around a pine keel over 100 feet long and covered with a double layer of intricately fitted cedar planking, thus clearly indicating its oceangoing character. Inside, 13 compartments held the residue of an exotic cargo of spices, shells, and fragrant woods, much of it originating in east Africa (see Asia's Undersea Archeology).

The Quanzhou wreck suggests that over a century before Zheng He's fabled voyages, the Chinese were already involved in ambitious trading exploits across the Indian Ocean. Even back then, their sturdy ships equaled the largest known European vessels of the period. By inventing watertight compartments and efficient "lugsails" that enabled them to steer close to the wind, Chinese shipbuilders remained ahead of the West in the following centuries.

Zheng He (1371-1433), the great Ming navigator Courtesy of Instructional Resources Corporation, www.historypictures.com

Exploits of the eunuch admiral

Zheng He commemorated his adventures on a stone pillar discovered in Fujian province in the 1930s. His mission, according to the pillar, was to flaunt the might of Chinese power and collect tribute from the "barbarians from beyond the seas." On his first trip, leading more than 60 massive galleons, Zheng He visited what would later become Vietnam and reached the port of Calicut, India. On his return, he battled pirates and established massive warehouses in the Straits of Malacca for sorting all the goods accumulated on this and subsequent voyages.

Landing at Somalia, he found himself offered such exotic items as "dragon saliva, incense, and golden amber."

While voyaging to India, the ships encountered a ferocious hurricane. Zheng He prayed to the Taoist Goddess known as the Celestial Spouse. In response, a "divine light" shone at the tips of the mast, and the storm subsided. This heavenly sign—perhaps the static electrical phenomenon known as St. Elmo's fire—led Zheng He to believe that his missions were under special divine protection.

The emperor launched Zheng He's fourth and most ambitious voyage in January 1414. Its destination was Hormuz on the Persian Gulf, where artisans strung together exquisite pearls and merchants dealt in precious stones and metals. While Zheng He lingered in the city to amass treasure for the emperor, another branch of the fleet sailed to the kingdom of Bengal in present-day Bangladesh.

To navigate throughout the Indian Ocean, Zheng He would have made use of the magnetic compass, invented in China during the Song dynasty. © WGBH Educational Foundation

Here the travelers saw a giraffe that the east African potentate of Malindi had presented to the Bengal ruler. The Chinese persuaded their hosts to part with the giraffe as a gift to the emperor and to procure another like it from Africa. When the giraffe arrived at the court in Nanjing in 1415, the emperor's philosophers identified it, despite its pair of horns, as the fabled chi'i-lin or unicorn, an animal associated with an age of exceptional peace and prosperity. As the fleet's merchants laid treasures from Arabia and India at the feet of the emperor, this omen must surely have seemed fitting.

The initial diplomatic contact with Malindi now encouraged Zheng He to plan a direct trading voyage to eastern Africa. Landing at Somalia on the coast, he found himself offered such exotic items as "dragon saliva, incense, and golden amber." But even these substances paled before the extraordinary beasts that were loaded on board his ships. Lions, leopards, "camel-birds" (ostriches), "celestial horses" (zebras), and a "celestial stag" (oryx) were shipped back to the imperial court. Here officials showered congratulations on Zheng He and bowed low in awe before the divine creatures that accompanied him.

End of an era

Toward the end of his seventh voyage in 1433, the 62-year-old Zheng He died and was said to have been buried at sea. Although he had extended the wealth and power of China over a vast realm and is even today revered as a god in remote parts of Indonesia, the tide was already turning against foreign ventures.

Impressive as they are, Chinese junks today are but pale shadows of medieval Chinese ships. © WGBH Educational Foundation

The conservative Confucian faction now had the upper hand. In its worldview, it was improper to go abroad while one's parents were still alive. "Barbarian" nations were seen as offering little of value to add to the prosperity already present in the Middle Kingdom.

The renovation of the massive Grand Canal in 1411 offered a quicker and safer route for transporting grain than along the coast, so the demand for oceangoing vessels plummeted.

Old men's folktales of shipwreck are among the few tangible relics of China's epic voyages of adventure.

In addition, the threat of a new Mongol invasion drew military investment away from the expensive maintenance of the treasure fleets. By 1503 the navy had shrunk to one-tenth of its size in the early Ming. The final blow came in 1525 with the order to destroy all the larger classes of ships. China was now set on its centuries-long course of xenophobic isolation.

Historians can only speculate on how differently world history might have turned out had the Ming emperors pursued a vigorous colonial policy. As it is, porcelain shards washed up on the beaches of east Africa and old men's folktales of shipwreck are among the few tangible relics of China's epic voyages of adventure.