The Field Museum in Chicago announced the news on Wednesday.
The joint expedition was led by Chapurukha Kusimba of the museum and Sloan Williams of the University of Illinois-Chicago. Researchers say the coin proves trade existed between China and eastern Africa decades before European explorers arrived in the place.
The coin is made of copper and silver. It has a square hole in the center so it could be worn on a belt. Scientists say it was issued by Emperor Yongle of China and his name is written on the coin.
Scientists from Kenya, Pennsylvania and Ohio also participated in the expedition. They also found human remains and other artifacts predating the coin.
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