The Military Policy Of Tang China Towards The Tibetan Kingdom

In the external relations of the Tang dynasty,the Tibetan Kingdom played a key role.In the reign of Emperor Taizong,the Tang government and the Tibetan Kingdom began to establish diplomatic links.After Princess Wencheng married to the Tibetan Kingdom,the Tibetan Kingdom began to be affected by the Tang Dynasty in both economic and cultural.At the beginning,the two countries were in harmony.However,when Emperor Gaozong ascended the throne,the Tibetan rulers' desire for expansion increased.In the third year of Longshuo,the Tibet occupied Tuyuhun,then reached Tang's prefectures in northwest,which made the conflicts between the two counties increased.At first,Emperor Gaozong adopted a policy of appeasement towards Tufan.But the threats from Tibet turned to be worse and worse,so Emperor Gaozong determined to fight back.Emperor Gaozong had launched two wars against the Tibet.Though the Tang army failed in both wars,the three armies which the Tang government established in the preparation for the second war were important.Among the three armies,the Heyuan army was located in the valley of Huangshui,the Jishi army was by the side of Yellow River and the Momen army was in the valley of Taoshui.These armies withstood the Tibetan army's invasion to the east effectively,and moved Tang's defensive line further to the west.These three armies also laid the military foundation for the Longyou Military Command and made the situation of confrontation between Tang and Tibet possible before the An Lushan Rebellion.When Wu Zetian came to power,she set up the Commission of the various armies of Longyou in northwestern borderland,which administered Longyou,Hexi and the Western Region.This is not only the beginning of coordinating military operations within a certain military unit,but also an embryonic stage of Longyou military Command.But by the time,the Commissioner is a temporary position.Only when faced with serious threatens,the Tang Court would appoint generals to this position.In the reign of Zhongzong and Ruizong,the relationship between the Tang court and the Tibetan Kingdom was eased.However,the Shenlong Treaty made in Zhongzong's reign and Ruizong's permition of granting Jiuqu Area to Princess Jincheng led to conflictions between the two countries in the following reign of Emperor Xuanzong.When it came to the reign of Emperor Xuanzong,the war between Tang and Tibet became more and more intense.The Tang government had to adjust the military policy and system correspondingly,which worth studying in depth.The Longyou Military Command was established by Xuanzong in the early of Kaiyuan period.In Kaiyuan period,both Longyou and Hexi Military Command had battles with Tibetans frequently.Tibetan armies often entered Hexi through Longyou,so when the Tibetan armies were stronger,the battlefield was in Hexi.If the Tang army got the upper hand,the battlefield would be pushed to Longyou,or around Tibetan fortresses near Longyou area.Because Longyou Military Command was the front against Tibet,it could show us the military policy of Xuanzong towards Tibet and Tibet's influence on the development of Tang's military system.During Emperor Xuanzong's reign,a lot of military reforms such as professional soldiers,the rule of Military Commander controlling finance,the system of Autumn guarding,the change from compulsory military service to mercenaries and the defense goal of each military command were all influenced by the Longyou Military Command.The battles between Tang and Tibet during Xuanzong's reign were not all provoked by Tibet.In fact,many battles were waged by Xuanzong.In this period,the Longyou Military Command took more and more important responsibilities in the war.To check all the military governors of Longyou,we can find that the selected governors got more and more attention from the Tang Court.And during the Tianbao Period,the appointments to let the Longyou Military governors to take the duty of the Hexi Military governor became common.Finally,Tang's military policy at Longyou had important impacts on the Tang-Tibet relationship and the turmoil at Northwestern region after the An Lushan Rebelion.It is a dynamic equilibrium on military confrontation between Tang and Tibet at Longyou,which contributed to the border negotiations between Tang and Tibet.It was the first time that Tang and alien regime demarcated specific boundary lines in the history of China.The Longyou Military Command was the frontline between Tang and Tibet,and the Tang government controlled this area mainly by military means.After the An Lushan Rebelion,the control of the Tang government on northwest got weaker and weaker,which is the reason why Longyou area was rapidly occupied by the Tibetan Kingdom.