Battle of Talas
The western expansion of the Tang Empire was checked in 751 by the defeat of a large expeditionary force led by General Gao Xianzhi in the Battle of Talas in the modern Fergana Valley, with the Abbasid victory attributable to the defection of the Karluk Turks in the midst of the battle. However, the Arabs did not proceed any further after the battle, and the Tang retained their Central Asian territories until the An Lushan rebellion.