The 600-year-old coin is made of copper and silver and has a hole in the center. It’s called a Yongle Tongbao and was issued by Emperor Yongle, who reigned during the Ming Dynasty between the years 1403 to 1425 AD. It was found on Manda, an island in Kenya, announced researchers from The Field Museum and the University of Illinois, and it’s a tangible piece of evidence of Chinese exploration and trade in Africa, years before European explorers reached this part of the world.

It’s easy to date the coin: it features the emperor’s name. Yongle was perhaps best know for starting the initial construction of Beijing’s Forbidden City, but he also sent huge fleets of ships, under the command of admiral Zheng He, out across the ocean to faraway lands.

UCLA‘s International Institute explains:

Upon the orders of the emperor Yongle and his successor, Xuande, Zheng He commanded seven expeditions, the first in the year 1405 and the last in 1430, which sailed from China to the west, reaching as far as the Cape of Good Hope. The object of the voyages was to display the glory and might of the Chinese Ming dynasty and to collect tribute from the “barbarians from beyond the seas.” Merchants also accompanied Zheng’s voyages, Wu explained, bringing with them silks and porcelain to trade for foreign luxuries such as spices and jewels and tropical woods.

The researchers who found the coin describe Zheng He as “the Christopher Columbus of China.” But this admiral’s fleet was much larger than Columbus’. Zheng He commanded as many as 317 ships with 28,000 crew members; Columbus had just three ships and fewer than 100 crew to command.

The Chinese expeditions started out closer to home, but a voyage that began in 1417 made it to Africa. The fleet’s treasure ships brought back strange animals—giraffes, zebras, and ostriches—to the court at home.

After Yongle’s death, though, successors soon banned foreign expeditions and destroyed much of the documentation of the Zheng He’s voyages. The coin provides one of the few tangible links between Africa and China at that time. As for Manda, where the coin was discovered, that island was home to an advanced civilization for around 1,200 years, but it was abandoned in 1430 AD, never to be inhabited again.

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