Conquest of the Western Turks The conquest of the Western Turks , known as the Western Tujue in Chinese sources , was a military campaign in 657 led by the Tang Dynasty general Su Dingfang against the Western Turkic Khaganate ruled by Ashina Helu . The Chinese war against the Western Turks began in 640 with the annexation of the Tarim Basin oasis state Gaochang , an ally of the Western Turks . Tang expansion into Central Asia continued with the conquest of Karasahr in 644 and Kucha in 648 . Su Dingfang ' s army defeated Helu at the battle of Irtysh River . The victory strengthened Tang control of Xinjiang and brought the regions formerly ruled by the Khaganate into the Tang empire . Puppet qaghans and military garrisons were installed to administer the newly acquired territories . The Tang Dynasty achieved its maximum extent as China ' s western borders reached the eastern frontier of the Arabic Umayyad Caliphate . Later on , Turkic revolts ended Chinese hegemony beyond the Pamir Mountains in modern Tajikistan and Afghanistan , but a Tang military presence remained in Dzungaria and the Tarim Basin . Central Asian culture absorbed artistic and political influences from Tang China , and the Turkic migrants serving under the Tang as soldiers and generals spread Turkic culture and language into Central Asia . Background . The empire of the Tang Dynasty ( June 18 , 618 – June 1 , 907 ) , successor of the Sui Dynasty , was a cosmopolitan hegemon and one of China ' s most expansive empires . Raids by the nomadic Khitans and Turks challenged Tang rule , and Tang rulers responded by pursuing strategies of divide and conquer , proxy war fare , tributes , and marriages . Hostilities between the Tang and the Western Turks had existed since the founding of the dynasty . Emperor Gaozu , the first emperor of the Tang Dynasty , aided the assassination of a Western Turk qaghan in November 2 , 619 . Facing the threat of both the Western and Eastern Turkic Khaganates , Gaozu ' s successor Emperor Taizong formed an alliance with the Western Turks against the Eastern Turks , adopting a policy of allying " with those who are far away to fight those who are close . " China ' s westward expansion began with their war against the Eastern Turks , or Eastern Tujue as they were called in Chinese records . Taking advantage of the political discord in the Eastern Turkic Khaganate , Taizong invaded and conquered the Eastern Turks in 629 , beginning a period of rule that would last for the next fifty years . The nomads were driven out of the Ordos region and southern Mongolia and Taizong was declared a Great Khan by the defeated tribes , who surrendered and submitted to Tang rule . Battles in the Western Regions . Many of the Tarim Basin oasis states were vassals or allies of the Western Turks . The oasis states Kashgar and Khotan surrendered to the Chinese in 632 , as did the kingdom of Yarkand in 635 . Tang military campaigns expanded further west against the remaining kingdoms of the Tarim Basin in southern Xinjiang beginning in 640 . The king of Gaochang refused to submit to the Tang Dynasty as a suzerain . In 638 , Emperor Taizong ordered a campaign led by general Hou Junji to invade Gaochang . Tang troops arrived in 640 and annexed the kingdom . A Western Turk army , sent to support Gaochang , retreated as the Tang forces approached . The nearby kingdom of Karasahr grew wary of the Chinese troops stationed at Gaochang , now under Tang domination . It refused to send tribute to the Tang court and formed an alliance with the Western Turks . A Tang campaign led by commander Guoxiao Ke captured the kingdom in 644 and installed a Tang loyalist as ruler . Military assistance by the Western Turks failed to deter the Tang forces . With the support of the Western Turks , the puppet ruler was later deposed , and another military campaign , led by the Tang general Ashina She ' er , a member of the Turkic Ashina royal family , arrived in 648 to re - establish Tang control . After conquering Karasahr , She ' er led his forces to the kingdom of Kucha . The army of Kucha , comprising 50 , 000 soldiers , lost to She ' er . The king of Kucha fled with his soldiers to the kingdom of Aksu . After a forty - day siege , the Kuchean ruler was captured and the Kucha forces surrendered on 19 January 649 . Tang military garrisons were installed in the region to administer the annexed oasis states . These garrisons , known as the Four Garrisons of Anxi , were located in Kucha , Kashgar , Khotan , and Karasahr . Campaign . Ashina Helu , a member of the Ashina royal family , was previously a general under Emperor Taizong commanding Tang forces in Gansu . He led a revolt against the Tang and migrated westward , declaring himself Shabulou Qaghan and ruler of the Western Turkic Khaganate . Helu ' s rise to power unified the divided Turkic tribes under a single leader . After he established himself as qaghan , Ashina Helu led repeated raids on Tang settlements to the east . He also attacked the Tarim Basin , bringing the territory under Turkic rule for the next six years . Emperor Gaozong , the successor of Taizong , responded by sending Tang forces consisting of a main division led by Su Dingfang , and another led by Ashina Mishe and Ashina Buzhen , Western Turk rivals of Ashina Helu . Su Dingfang was a commander from south - central Hebei who , earlier in his career as an officer , was responsible for leading the attack against the military camp of Illig Qaghan , qaghan of the Eastern Turks . He also gained military experience as a leader of a regional militia during the civil war fought between the transition from Sui to Tang . As a general with experience in Central Asia , he was familiar with the culture of the steppes and had formal and personal relationships with non - Han Chinese ethnic groups . In 655 , he was one of nine multi - ethnic commanders , along with the Turkic general Ashina Zhong , second cousin of Ashina She ' er , invited by Emperor Gaozong to a military music event . Su Dingfang ' s forces comprised Tang soldiers and 10 , 000 Uyghur horsemen . The Uyghur troops were provided by Porun , son of the Uyghur leader Tumidu Eltabar and enthroned by Taizong . The Uyghurs were allied with Tang China , who had supported their revolt against the reign of the Xueyantuo , a tribe of Tiele people . Porun joined Su Dingfang as a vice commander of the Uyghur cavalry in the military campaign against the Western Turks . The commanders of the Uyghur cavalry were the Yanran Protector - General and Vice Protector - General , administrators of the Yanran Protectorate near the Tang Xishouxiang military garrison . Su ' s army marched through the Central Asian steppes from Ordos , Inner Mongolia to the Altai Mountains region . His troops left Ordos in March and arrived in Kyrgyzstan in November , a journey spanning 3 , 000 miles across steppes and desert . Su avoided stopping at the resource rich oasis states , and historian Jonathan Karam Skaff speculates that the Chinese troops may have relied on livestock for food instead of a supply train , a tactic used by the steppe nomads . The campaign continued through the winter , when the steppes were covered in snow . Describing the journey ' s ordeal , Su Dingfang is reported to have said : " The fog shed darkness everywhere . The wind is icy . The barbarians do not believe that we can campaign at this season . Let us hasten to surprise them ! " Commanders in the Tang army were familiar with the political culture of nomadic empires . Nomadic alliances were formed through distributing war plunder and ensuring the security of tribal property , and grew tenuous when rulers failed to deliver their promises . The Chinese understood that disaffected tribes were vulnerable to switching allegiances , and used this to their advantage . Su Dingfang recruited tribes to side with Tang , and these former tribal vassals of the Western Turks contributed additional soldiers . The tribe Chumukun offered their support after they were defeated by Su , and the tribe Nishu aided Su after their children and wives , originally captured by Helu , were returned along with gifts offered by the Tang . The battle of Irtysh River was fought along the Irtysh River near the Altai Mountains . Helu ' s forces , consisting of 100 , 000 cavalry , were ambushed by Su as Helu chased decoy Tang troops that Su had deployed . Helu was defeated during Su ' s surprise attack , and lost most of his soldiers . Turkic tribes loyal to Helu surrendered , and Helu escaped to Tashkent in modern Uzbekistan . The retreating Helu was captured the next day after residents of Tashkent handed the qaghan over to the Tang . On the way back to the Tang capital , Helu is reported to have written : I am a defeated and ruined war captive , that ' s it ! The former emperor [ Taizong ] treated me generously , but I betrayed him . In my present defeat , Heaven has vented its fury at me . In the past I have heard that Han law stipulates that executions of men be carried out in the city marketplace . When we arrive in the capital , I request to Zhaling [ the tomb of the previous Tang emperor Taizong ] to atone for my crimes to the former emperor . This is my sincere desire . Gaozong received Helu ' s plea and agreed to his request , despite a Tang law ordering the execution of captured rebel generals and kings . In accordance with Confucian ritual s , he was sent to Taizong ' s tomb where Gaozong spared his life , and then to the capital ' s Ancestral Temple where the captive was presented again , mirroring ancient rituals celebrating victorious armies . Helu felt disgraced by Taizong and committed suicide a year later while still in captivity . He was buried in a mound decorated with a stele outside the emperor ' s park . The tomb served as a military trophy , visible to the emperor ' s visitors entering the park , symbolizing the loyalty of the qaghan to the emperor and the Tang military victories against the Western Turks . Historical significance . Aftermath . The conquest strengthened Tang rule over modern Xinjiang , administered by the Anxi Protectorate , and led to Tang suzerainty over the regions previously under the control of the Western Turks . The fall of the Khaganate brought the Altai Mountain region under Tang control and the residing Three Qarluq tribes were governed in newly established prefectures led by tribal chiefs , now commander - in - chiefs under the Tang . Another prefecture , the Jinman Bridle Prefecture , was created for the Chuyue tribes living in the southern Dzungar basin . The Amu Darya valley , the Tarim Basin , and the area beyond the Pamir Mountains , all former suzerains of the Western Turks , were placed under Tang control . Su continued his career as military general , and later commanded Tang forces in a war against Baekje in 660 . The Tang Dynasty achieved its maximum extent following its conquest of the Khaganate . The inhabitants of the new territory did not become sinicized like many of the other kingdoms and tribes conquered by the Tang . Tang military activity in Central Asia brought in a wave of Turkic migrants serving in the Tang military as soldiers and generals , leading to the spread of Turkic language and culture . Central Asia also absorbed cultural influences from Tang China . Central Asian art incorporated Tang stylistic features , like the sancai three color glaze used in pottery . Chinese coins remained in circulation in Xinjiang after the decline of the Tang . Cultural remnants of Tang architectural influence are still visible in the Buddhist architecture of Dunhuang . The sheer size of the newly conquered lands made it difficult to govern through the Tang military garrisons . The Tang emperor Gaozong appointed two puppet qaghans to rule over the Western Turks , who were later overthrown in a rebellion that began in 662 . The revolt reduced Tang ' s western extent to Beshbalik , Dzungaria in northern Xinjiang and ended direct Tang control of Central Asia beyond the Pamir Mountains in modern Tajikistan and Afghanistan . The expansion of the Tibetan Empire from the south threatened China ' s hold on southern Xinjiang . Tibet invaded the Tarim Basin in 670 , but Tang forces regained the area in 693 and Kashgar in 728 , restoring the Anxi Protectorate and Four Garrisons . At its maximum extent , Tang expansion brought China into direct contact with the rising Umayyad Caliphate . China ' s western borders reached the eastern frontier of the Caliphate . Following the Arab defeat of Sassanid Persia in 651 , the Caliphate began its expansion into Central Asia , competing with the Tang ' s sphere of influence in the region . Chinese and Islamic troops finally clashed at the Battle of Talas in 751 . The Chinese lost against the Arabs , now under Abbasid rule , and the Arab army captured Chinese papermaking craftsmen . An Arabic record of the conflict claims that the battle led to the introduction of papermaking to the Islamic world . Puppet qaghans . The Tang emperor Gaozong installed two puppet qaghans , the cousins Ashina Buzhen and Ashina Mishe , and controlled the region by proxy . Buzhen and Mishe were enemies of Helu who had aided Su Dingfang during his campaign against Helu and the Western Turkic Khaganate . Gaozong divided the ten tribes of the area among the two cousins . Buzhen governed half of the tribes located in the west , while Mishe governed the other half located in the east . The son of Buzhen , Khusrau , and the son of Mishe , Yuanqing , resided in Chang ' an , the capital of Tang , while their fathers administered the former khaganate as qaghans . Empress Wu Zetian sent Yuanqing and Kusrau westward in 685 to succeed their fathers as proxy rulers . Neither of qaghans were able to successfully exert control . Turkic tribes resisted Yuanqing ' s rule , defeating the qaghan and forcing Yuanqing to return to Chang ' an . Kusrau was able to bring the western tribes temporarily under his rule , but was defeated in 690 during an invasion by the Second Turkic Khaganate , and he too was forced to escape the region with his loyalists . Later attempts to install puppet qaghans failed , and the title was reduced to a symbolic position in the Tang court .