He had earlier visited places like Malacca, Hormuz, Siam, and Ceylon during seven voyages.  
After being captured as a boy in Yunnan, he made a name for himself in the military under Prince Yan, who would go on to overthrow the Jianwen emperor to become the Yongle emperor.  This Muslim son of a hajji defeated King Alagonakkara, and the Hongxi emperor later made him a garrison commander in Nanjing.  He had earlier visited places like Malacca, Hormuz, Siam, and Ceylon during seven voyages.  For 10 points, name this eunuch admiral and emissary for the Ming Dynasty.
After being captured as a boy in Yunnan, he made a name for himself in the military under Prince Yan, who would go on to overthrow the Jianwen emperor to become the Yongle emperor.  
{Zheng} He [or {Cheng Ho}; or {Ma} He; or {Ma Sanbao}]