The Battle of Kharistan, 737

I never understood the fus about Talas, the political significance of that battle is negligible, a pinprick damage China, yet considered by some "historians" as a decisive battle.

The real desicive batttle is Kharistan, against the Turgesh.

In the 720s the Turgesh was the biggest threat to the Islamic Empire.

Their kingdom was established in 716 with the help of the Chinese and with China's support repulsed the Eastern Turks and projected their power over central Asia.

In 724 they annihilated a Arab army in an important battle called Day of Thirst. The first full scale battle between the Arabs and the Turgesh.

After that battle the Arabs were on the defensive getting pushed back slowly across the Oxus, finally in 729, their Khan Sulu took a campaign that completely drove the Arabs out of central Asia with the exception of Samarkand.

The Turgesh threatened to overrun the whole of Khurasan and Arab East.

The central authority in Damascus was so alarmed that it despatched Asad as the new governor, Asad knew that Arab powe ralone could not defeat the Turgesh, he need support of the local population. He gave many locals autonomy. But many felt betrayed and the Caliph had to order him back. The Caliph made Hishan the new governor of Kurasan. But Hishan only made the situation worse as the locals rebelled and joined the Turgesh. The Hephtalites under nominal Arab soverignty quickly took the situation to cause trouble too. In the end the Caliph had to order Asad back to power. Asad was fortunate enough to pursuade the Hephtalites to join against the common enemy Turgesh.

In 737, Sulu Khan of Turgesh again invaded with 40,000 troops, he won some skirmish captured a few fortress, and raided deep into Khurasan, threatening Merv itelf. But in a stroke of luck. He dispersed his force too thin, and the Arabs and their allies manage to surprise him and decisively defat his troops, most of Sulu's force were gone and he escaped back to Turgis territory, a year later he was killed in a brawl and the Turgesh fell to the mounting Chinese power. They ceased to be a menace to the Arabs.

This Battle of Kharistan was extremely important, it halted Turgesh expansion into the East. Kept Arab Khurasan intact in the height of danger from internal and external threat. It might even have prevented the Abbasid rebellion if Sulu overran Merv where the rebellion started.

This, not Talas should be ranked among the decisive battles of history.

Simple political interests

The major power of the steppe before the establishment of the Turgis power was the Eastern Tujue under Mocho. He controlled the lands of the Turgis until 714 when the Western Tujue revolted, at the same time Mocho sent a corps of invade BeiTing under his son. But that force was destroyed by the protector general and Mocho's son was killed. This victory made an impression on the Western Tujue. The Tang follows by capturing Tokmak and garrisoned there to prevent Mocho from taking it. Then in 716 it gave Sulu a title and made it the representative of Tang power in central Asia. However things aren't as well as the Tang planned. By 718 Sulu declared himself Khaghan, and despite paper submission by accepting the Tang fish bags(imperial symbles of submission) made his own political moves. It only submit to Tang for trade purpose and still nominally represent Tang. Yet because of its growing power, in the next year it captured the Tang garrison of Tokmak and later allied with the Tibetans to ravage the Tarim Basin. Xuan Zong finally decide that the Turgis have to be punished, and in 736 a.d. mobilized an army of 10,000 decicively defeated the Turgis in the Tarim and forced Sulu to surrender. Xuan Zong originally wanted to finish the Turgis completely by occupying their whole territory, but finally accepted the Turgis surrender because he knew that resistance is still strong in the Turgis land, and its difficult to destroy the kingdom in just a campaign. With its eastward attacks halted, Sulu turn west only to be halted again by the Arabs. Then after the Turgis broke up in 738, the Tang protector general marched to the Turgis land and killed Sulu(different accounts say differently), supported another Khan and finally subduing all of the Turgis territory by 739.