Yongle Emperor
Gang Bing is most notable for his act of self-castration as a display of loyalty to his emperor. He served under the Yongle Emperor, the third emperor of the Ming dynasty who ruled over China from 1402 to 1424. Historical accounts describe Gang Bing as the emperor's favorite general. Because of this, the Yongle Emperor placed Gang Bing in charge of the palace in Beijing while he left for a hunting expedition.