query: When did the Xiongnu exist?
passage: Xiongnu
The Xiongnu [ɕjʊ́ŋ.nǔ] (Chinese:匈奴; Wade–Giles:Hsiung-nu) were a confederation[3] of nomadic peoples who, according to ancient Chinese sources, inhabited the eastern Asian Steppe from the 3rd century BC to the late 1st century AD. Chinese sources report that Modu Chanyu, the supreme leader after 209BC, founded the Xiongnu Empire.[4]
passage: Tocharians
In 177 BC, the Xiongnu drove the Yuezhi from western Gansu, causing most of them to flee west to the Ili Valley and then to Bactria.
The Xiongnu then overcame the Tarim statelets, which became a vital part of their empire.
The Chinese Han dynasty determined to weaken their Xiongnu enemies by depriving them of this area.
This was achieved in a series of campaigns beginning in 108 BC and culminating in the establishment of the Protectorate of the Western Regions in 60 BC.
The Han government used a range of tactics, including plots to assassinate local rulers, direct attacks on a few states (e.g. Kucha in 65 BC) to cow the rest, and the massacre of the population of Luntai (80 km east of Kucha) when they resisted.
The Han controlled the Tarim states intermittently until their final withdrawal in 150 AD.