Protectorate of the Western Regions

The Protectorate of the Western Regions () was an imperial administration imposed by Han China – between the 2nd century BCE and 2nd century CE – on many smaller and previously independent states, which were known in China as the "Western Regions" ().
"Western Regions" referred mostly to areas west of Yumen Pass, especially the Tarim Basin. These areas were later regarded as Altishahr (southern Xinjiang, excluding Dzungaria). Previously, "western regions" was used more generally with Central Asia and sometimes even included parts of South Asia. 
The protectorate was the first direct rule by a Chinese government of the area. It comprised various vassal protectorates, under the nominal authority of a Protector-General of the Western Regions, appointed by the Han court.
History.
In the Han–Xiongnu War of the 2nd Century BCE the Chinese state established a military seat at Wulei (near present-day Cedaya 策达雅, in Bugur/Luntei County). They aimed to control the diverse peoples and cultures of the Western Regions at the time, including several groups who originated in Western Eurasia and/or who spoke Indo-European languages. These peoples included the Tocharian-speaking city-states, such as "Ārśi" (Arshi; later Agni/Karasahr), "Kuča" (Kucha), "Gumo" (later Aksu), "Turfan" (Turpan), Loulan (Krorän/Korla). By controlling the Western Regions, the Chinese would also keep the Xiongnu away from Inner China. The peoples of oasis city-states of Khotan and Kashgar spoke the Saka language, one of the Eastern Iranian languages.
The seat was later shifted to Taqian (or Tagan; near modern Kucha), during the Eastern Han dynasty.
Officially established in 59 or 60 BCE, Protector-General was the highest military position in the west during its existence. During its peak in 51 BCE, the Wusun nation was brought under submission. After at least 18 different protector generals, of whose names only 10 of their names are known, the post was abandoned, by the time of Wang Mang's Xin dynasty in 23 CE.
In 74 CE, Emperor Ming of Han and his successor awarded the position (now with administrative obligations as well) to general Chen Mu. From 83 CE and the appointment of Ban Chao, the Protector-General was known as the Chief Official of the Western Regions.
On 29 July 107, a series of Qiang uprisings in the areas of Hexi Corridor and Guanzhong forced the abandonment of the post, although it was resumed in 119.
In the 7th century, a successor administration, the Protectorate General to Pacify the West was established at Xizhou (Turpan) and moved later to Kucha.
Coins from the period, with inscriptions in both Chinese and the Kharoshthi script used by local Indo-European languages, have been found in the southern Tarim Basin.