Zheng He’s trea sure ships were oceangoing monsters, capable of sailing through storms across the oceans of the world for weeks at a time. Carrying more than a thousand tons of cargo, they could reach Malacca in five weeks, the Strait of Hormuz in twelve. Staterooms were provided for ambassadors and their staffs returning to India, the Persian Gulf, and Africa. More than 180 medical officers were on the admiral’s staff; each ship had a medical officer for every 150 men, and they took on sufficient citrus and coconuts to protect them from scurvy for two months. Caulkers, sailmakers, anchor repairers, scaffolders, carpenters, and specialists in tung oil application maintained the ships during the voyage. In addition, the ships carried interpreters who could communicate with rulers in India, Africa, and Europe—in Hindi, Swahili, Arabic, and Romance languages. As with all Chinese expeditions, astrologists and geomancers accompanied the fleets.
While Venetian galleys were primarily protected by archers, Chinese ships were armed with gunpowder weapons—bombards, fragmentation mortars, cannons, flaming arrows, even shells that sprayed excrement over their targets. With these awesome weapons, Admiral Zheng He would have no difficulty destroying pirate fleets. A contest between a Chinese fleet and a rival navy would resemble that between a shark and a minnow. In his final voyage, Zheng He commanded fleets more than ten times the size of Nelson’s at Trafalgar.2
However, there were two major distinctions between this final voyage and previous trips. First, huge improvements in cartography, navigation techniques, and ship construction made the voyages safer and their destinations more likely to be reached. Second, the principal purpose of this voyage was to present foreign rulers with the Xuan De calendar and with charts and navigational aids to enable foreign rulers to return tribute to China. When Zheng He’s junks returned in 1434, the Xuan De emperor, Zhu Zhanji, was able to claim that “ten thousand countries [are] our guests.”3 In the years immediately thereafter, a dozen countries paid tribute to the emperor, including an enormous delegation from Egypt.
Thanks to the research of Tai Peng Wang, we are able to follow the precise route of Zheng He’s and Hong Bao’s fleets to Calicut. Xi Feilong, Yang Xi, and Tang Xiren, in their recent discovery and analysis of The Charts of Zheng He’s Voyages, have reproduced Zheng He’s route and identified the specific stars his navigators used to determine latitude and longitude on the way to India.
Sailing with the monsoons across the Indian Ocean, their point of departure on October 10, 1432, was Pulau Rondo (Banda Atjeh) on the northwest tip of Sumatra (6°04′ N, 95°07′ E). Zheng He’s book of charts describes how by “gauging the vertical positions of the given stars above the horizon in the east, west, north, and south (they) reached Sri Lanka.”
The choice of stars (more accurately star groups—some contain multiple and binary stars) used by Zheng He’s navigators for their Indian Ocean crossing at first appears baffling. The right ascensions (“longitude in the heavens”) are Poseidon, twenty hours, Vega, eighteen hours, Sagittarius, nineteen hours, and Gemini, seven hours. So the positions obtained from their mea surements would correspond to their right ascension and the distances from the stars illustrated by the lines CD, EF, GH, and IJ on Fig 6 on our website. That is, an approximate line of 015/195 (seven hours/nineteen hours). Why do all the chosen stars have approximately the same right ascensions? Why not select different stars from different parts of the heavens?
The answer becomes clear when Polaris is considered. Polaris is at 90° elevation at the North Pole and 0° at the equator. Thus the height of Polaris in the sky (altitude) equals latitude—the line AB, Fig 6 on our website. By mea suring Polaris’s height, a navigator could ascertain his latitude. The best stars to determine longitude would be at right angles to Polaris, that is, stars with right ascensions of 90 and 270 degrees (six and eighteen hours).
This discovery of Tai Peng Wang and his colleagues enables us to refine how Zheng He’s sailors determined latitude and longitude. For latitude, they used the sun at midday (meridian passage) and Polaris by night in the north. For longitude, they used those stars in the ephemeris tables that had right ascensions nearest six or eighteen hours or, alternatively, the moon. (I was a submarine navigator for four years and never thought of such an ingenious solution. One would have needed only two looks through the periscope—when one was at most risk—one at Polaris another at Pollux.)
Wang Jinghong, another admiral, would lead his fleet to the Persian Gulf.
In this chapter, we describe the passage of Zheng He and Hong Bao, then follow the voyage of a much smaller detachment from Hong Bao’s fleet, which sailed up the Red Sea to Cairo and the Mediterranean—following in the wake of Zheng He’s 1408 voyage to the Mediterranean.
On November 18, 1432, when the fleets were south of Sri Lanka, Zheng He ordered Hong Bao to lead the fleet to Calicut, their next port of call. A commander-in-chief does not order one of his flag officers to lead the fleet into harbor if he himself intends to be present. This means that Zheng He was detaching part of his fleet under the command of Hong Bao.4
We know from the charts of Zheng He’s voyages that Hong Bao left Calicut for Dandi Bandar farther up the coast (16° N, 73° E), crossing the Arabian Sea on a course of approximately 330 to make landfall at Jebel Khamish (22°25′ N, 59°27′ E). After a few days he pushed on to Bandar ‘Abbas, arriving on January 16, 1433. Hong Bao’s fleets returned to Calicut on March 25 and sailed for China on April 9, reporting there the sad news that Zheng He had “passed away.”
How did Hong Bao know that Zheng He had passed away? After his order to Hong Bao, Zheng He seems to have vanished. In my view, for reasons to be described in a later book, after detaching Hong Bao, Zheng He sailed for Africa and North America, settling near what is now Asheville, North Carolina, where he died.
Ma Huan, the historian aboard Zheng He’s fleet,5 describes Calicut in detail. Almost a tenth of Ma Huan’s book is devoted to this city-state, which had become a very important forward base for Zheng He’s fleets. Ma Huan, a Muslim, was delighted to find there were more than twenty mosques for a Muslim population of thirty thousand. He gives a detailed account of how trade was conducted between representatives of the trea sure fleet and local merchants and brokers. After negotiations, all parties would clasp hands and swear that the agreed prices would never be repudiated.
These fascinating accounts are mirrored in those of Niccolò da Conti, who had reached Calicut in 1419. As Richard Hall points out in Empires of the Monsoon, Ma Huan and Niccolò da Conti’s descriptions are almost the same word for word,6 not least in the descriptions of the Indian test for guilt (the accused’s finger was dipped in boiling oil; if the finger was burned, it signified guilt).
Niccolò accurately describes construction of the Chinese junks, so I am confident that he boarded one of Zheng He’s junks in 1421, which would have given him the ideal opportunity to acquire a map. Just such a map, as I will describe later, turned up in Venice before 1428, and a copy can be seen today in the Doges’ Palace. (Although Niccolò da Conti may not have returned to Venice until 1434, in the 1420s he had entrusted his mail to a friend, Piero Tafur, who took it to Venice on his behalf.)
On his 1432 voyage, Hong Bao did not stay long in Calicut. When he arrived, Calicut merchants were about to leave for Tianfang (Egypt) in their own fleet. Hong Bao seized the opportunity, detaching two junks and seven senior officers for a trade delegation laden with silks and porcelains, which joined the Calicut fleet.7