Western Turkic Khaganate
The Anxi Protectorate was created in Xi Prefecture (Gaochang) after the Tang dynasty successfully annexed the oasis kingdom in 640. The protectorate was moved to Qiuci in 648 after the Tang dynasty defeated Kucha. However, due to local unrest with support from the Western Turkic Khaganate the Tang protector general was assassinated and the protectorate was moved back to Xi Prefecture in 651. When the Tang dynasty defeated the Western Turkic Khaganate in 658, the protectorate headquarter was moved back to Qiuci. The full establishment of the Four Garrisons, and with them a formal Tang military protectorate over the Tarim Basin, is therefore dated to 658 after Ashina Helu's defeat.