section_path: Military and foreign policy/Protectorates and tributaries
section_name: Protectorates and tributaries
paragraph_text: Protectorates and tributaries
  
  The 7th and first half of the 8th century are generally considered to be the era in which the Tang reached the zenith of its power. In this period, Tang control extended further west than any previous dynasty, stretching from north Vietnam in the south, to a point north of Kashmir bordering Persia in the west, to northern Korea in the north-east.
  
  Some of the kingdoms paying tribute to the Tang dynasty included Kashmir, Nepal, Khotan, Kucha, Kashgar, Silla, Champa, and kingdoms located in Amu Darya and Syr Darya valley. Turkic nomads addressed the Emperor of Tang China as Tian Kehan. After the widespread Göktürk revolt of Shabolüe Khan (d. 658) was put down at Issyk Kul in 657 by Su Dingfang (591–667), Emperor Gaozong established several protectorates governed by a Protectorate General or Grand Protectorate General, which extended the Chinese sphere of influence as far as Herat in Western Afghanistan. Protectorate Generals were given a great deal of autonomy to handle local crises without waiting for central admission. After Xuanzong's reign, jiedushi were given enormous power, including the ability to maintain their own armies, collect taxes, and pass their titles on hereditarily. This is commonly recognized as the beginning of the fall of Tang's central government.