A new examination of communication flows between the Hexi Corridor,Xi-yu,and the Tang court after the fall of Hexi and Long-you(陇右,or the western section of Gansu)regions to the Tibetan empire
After the Tibetan empire seized Liang-zhou(凉州),the Hexi town communicated with the Tang court through the Uighur Khaganate.During the rebellion of Pugu Huai'en(仆固怀恩),this communication line was severed.After the Chang-quan(长泉)Incident,emissaries from both the Hexi town and Yi-xi-ting(伊西庭)reported to Chang'an via the Uighur territory.During Li Yuanzhong's(李元忠)reign over Bei-ting(北庭),the Tang court conferred official appointments to officers in Yi-zhou(伊州),and many eunuchs were dispatched to Bei-ting as envoys.Based on the records of officer ap-pointments and promotions of the Hexi Garrison,it can be inferred that Sha-zhou(沙洲)also main-tained a close contact with the Tang court before being besieged by the Tibetans.From the 10 th year of Da-li(大历)era(775 CE.)to 1st year of Jian-zhong(建中)era(780 CE.),communications between the Tang court and Bei-ting was severed,and only resumed through Uighur Khaganate by the 2 nd year of Jian-zhong(建中)era.During the rebellion of Zhu Ci(朱泚),connections between the two sides a-gain broke off.It was only until the 2 nd year of Zhen-yuan(贞元)era that contacts between Bei-ting and four towns in the Hexi region and the Tang court were restored.The travel route of Banla Ruo(般剌 若)to the Kasmira Kingdom in the 6 th year of Zhen-yuan era suggests that emissaries from the four towns of Hexi region returned to Bei-ting via Chang'an,Taiyuan,Zhenwu,and finally through the Uighur Khaganate during the Zhen-yuan(贞元)era.
Hexi,Bei-tingFour Towns of the Hexi Regionthe Tang Court