In 1421, China's Ming dynasty Yongle Emperor ordered principal envoy grand eunuch Li Xing and grand eunuch Zhou Man of Zheng He's fleet to convey an imperial edict with hats and robes to bestow on the king of Aden. The envoys boarded three treasure ships and set sail from Sumatra to the port of Aden. This event was recorded in the book ''Yingyai Shenglan'' by Ma Huan who accompanied the imperial envoy.