of Timur, who intended to invade China, the relations between the Yongle Emperor's China and Shakhrukh's state in Persia and Transoxania state considerably improved. Both the Chinese envoy to Samarkand and Herat, Chen Cheng, and his opposite party, Ghiyāth al-dīn Naqqāsh, left detailed accounts of their visits to each other's country. The greatest diplomatic highlights of the Ming period were the enormous maritime tributary missions and expeditions of the admiral Zheng He (1371–1433), a favored court eunuch of the Yongle Emperor (r. 1402–1424). Zheng He's missions docked at ports throughout much of the Asian world, including those in Borneo, the Malay state of the Malacca Sultanate, Sri Lanka, India, Persia, Arabia, and East Africa. Meanwhile, the Chinese under the Yongle Emperor invaded northern Vietnam in 1402, and remained there until 1428, when Lê Lợi led a successful native rebellion against the Chinese occupiers. Large tributary missions such as these were halted after Zheng He, with periods of isolationism in the Ming dynasty, coupled with the need to defend China's large eastern coastal areas against marauding wokou pirates. Although it was severely limited by the state, trade was overall not forbidden. After 1578, it was completely liberalized. Upon their arrival in the early 16th century, the Portuguese Empire traded with the Chinese at Tamão, despite some hostilities exchanged between both sides. The Chinese also traded avidly with the Spanish, sending numerous trade ships annually to the Philippines in order to sell them Chinese goods in exchange for mita-mined silver from the New World colonies of Spain. There was so much Spanish silver entering China that the Spanish minted silver currency became commonplace in Ming China. The Chinese attempted to convert the silver currency back to copper currency, but the economic damage was done. In 1524, Beijing was visited by representatives of the Ottoman Empire. Meanwhile, the Chinese under the Wanli Emperor (r. 1572–1620) became engaged in a somewhat costly war defending Joseon Korea against Japan. The Japanese regent Toyotomi Hideyoshi (1537–1598) and his predecessor Oda Nobunaga (1534–1582) brought about the prosperous Azuchi-Momoyama period in feudal Japan, putting an end to the turbulent era of the Sengoku period. However, the Japanese staged an enormous invasion of Korea from 1592 to 1598. The aim of the Japanese was to ultimately invade prosperous Ming China, but in order to do so it would need to use the Korean Peninsula as a staging ground. Throughout