Indian Ocean trade routes were sailed by Arab traders. Between 1405 and 1421, the Yongle Emperor of Ming China sponsored a series of long range tributary missions under the command of Zheng He (Cheng Ho). The fleets visited Arabia, East Africa, India, Maritime Southeast Asia and Thailand. But the journeys, reported by Ma Huan, a Muslim voyager and translator, were halted abruptly after the emperor's death and were not followed up, as the Chinese Ming Dynasty retreated in the "haijin", a policy of isolationism, having limited maritime trade.