Jianwen Emperor
Some parts of the historical text "History of Ming", the authoritative history of the Ming dynasty, mentioned that one of the reasons behind why the Yongle Emperor sponsored the admiral Zheng He's treasure voyages in the early 15th century was that the emperor wanted Zheng He to help him search for the Jianwen Emperor, who was believed to have survived and fled to Southeast Asia. Other records relate that decades later, the Jianwen Emperor returned to the imperial palace and lived the rest of his life in obscure retirement.