It seems now to be a common occurrence for new archaeological discoveries to reveal new historical evidence that threatens to topple age-old theories. Researchers are having to head back to the unfamiliar territory of the drawing board as they seek to re-think their evidence and struggle to keep old ‘truths’ relevant.

In yet another of such moments, a rare 600-year-old copper and silver disk discovered on the island of Manda at the Kenya Coast, seems to suggest that China, not Portugal, may have been the first outsiders to sail around Africa to India and back in the late 15th century.

Bearing the name of Chinese emperor Yongle, head of the Ming dynasty, the rare coin, with a square hole in the middle, was unearthed in early December 2012 by Charles Kusimba from Chicago’s Field Museum and Sloan R. Williams from the University of Illinois on the first day of a 3-month dig conducted on Manda island.

Researchers believe that the coin, which was issued between 1403 and 1425, may prove that the Chinese were already trading with the eastern Coast of Africa long before the Portuguese arrived in the scene.

They speculate that it may have been Commander Zheng He (1371–1433), a court eunuch, mariner, explorer, diplomat and fleet admiral, who commanded expeditionary voyages to South-east Asia, South Asia, the Middle East and East Africa from 1405 to 1433 in pursuit of expanding Chinese political and trade influence across these territories.

These expeditions were short-lived and came to a halt upon the death of Emperor Yongle because his successors did not value international trade and so they banned all manner of exploration of the external world. It is believed this paved way for the more well-known European explorers like Vasco Da Gama and Christopher Columbus to discover new worlds and trade in goods like ivory and silk.

Once the rare coin is authenticated, it will bring centuries of archaeological theories crushing and call for the rewriting of history to set the facts right.

This will also trigger greater interest in the Manda dig site as archaeologists rush in to try and unearth more clues to the trading relationship between Europe and Asia. The dig site is regarded as the oldest in Sub-Saharan Africa.