Born in 1371, Zheng He was captured at the age of 10 by Chinese troops, and castrated. But in a remarkable change of fortune, he joined the household of Prince Zhu Di, son of the Emperor. The Prince was so impressed that when he ascended to the throne, he gave Zheng He command of the greatest armada the world has ever seen. Over thirty years, Zheng He led vast expeditions to India, the Middle East and Africa, covering 25,000 miles of ocean.