Ming Shilu
A 1499 entry in the Ming Shilu recorded that 13 Chinese men from Wenchang including a young man named Wu Rui were captured by the Vietnamese after their ship was blown off course while traveling from Hainan to Guangdong's Qin subprefecture (Qinzhou), after which they ended up near the coast of Vietnam, during the Chenghua Emperor's rule (1447–1487). Twelve of them were enslaved to work as agricultural laborers, while the youngest, Wu Rui (吳瑞) was selected for castration since he was the only young man and he became a eunuch attendant at the Vietnamese imperial palace in Thang Long. After years of service, he was promoted at the death of the Vietnamese ruler in 1497 to a military position in northern Vietnam. A soldier told him of an escape route back to China and Wu Rui escaped to Longzhou. The local chief planned to sell him back to the Vietnamese, but Wu was rescued by the Pingxiang magistrate and then was sent to Beijing to work as a eunuch in the palace.