A team of Chinese archeologists arrived in Kenya last week, headed for waters surrounding the Lamu archipelago on the country's northern coast. They hadn't made the trip to study local history. They came to recover a lost Chinese past.

In the early 1400s, nearly a century before Vasco da Gama reached eastern Africa, Chinese records say that the great admiral Zheng He took his vast fleet of treasure ships as far as Kenya's northern Swahili coast. Zheng visited the Sultan of Malindi, the most powerful...