Zheng He was born the second son of a family from Yunnan, whose ancestors included several governors of the region under the Yuan dynasty. Following the Hongwu Emperor's overthrow of the Yuan, a Ming army invaded Yunnan and captured and castrated Zheng He. In 1381 he was sent to serve Zhu Di, Prince of Yan, later to become the Yongle Emperor, and quickly became one of the prince's closest companions. In 1402 he would command the prince's expedition to capture Nanjing and claim the Dragon Throne.