In 215 BC , Qin Shi Huangdi ordered Request General Meng Tian to set out Military_operation against the Xiongnu tribes in the Ordos region , and establish Building a frontier region at the loop of the Yellow River .

Believing that the Xiongnu were a possible threat Warning , the emperor launched a preemptive strike Attack against the Xiongnu with the intention to expand Expansion his empire .

Believing that the Xiongnu were a possible threat Warning , the emperor launched a preemptive strike Attack against the Xiongnu with the intention to expand Expansion his empire .

Later in the year , Meng Tian succeeded Conquering in defeating Conquering the Xiongnu , driving Hold them from the Ordos and seizing Hold their homeland .

After the catastrophic defeat Conquering at the hands of Meng Tian , the Xiongnu leader Touman was forced Hostile_encounter to flee Escaping far north into the Mongolian Plateau .

As a result of the northward expansion Expansion , the threat Warning that the Qin empire posed Causation to the Xiongnu ultimately led to Causation the reorganization of the many different Xiongnu tribes into a confederacy .

As a result of the northward expansion Expansion , the threat Warning that the Qin empire posed Causation to the Xiongnu ultimately led to Causation the reorganization of the many different Xiongnu tribes into a confederacy .

In the second century BCE the region became Becoming part of the Xiongnu empire , a confederation of nomads centered Placing on present-day Mongolia .

The Tarim Basin was first referred to as `` Xiyu '' ( ) under the Han dynasty , which drove Motion the Xiongnu out of the Tarim Basin in 60 BCE ( Han–Xiongnu War ) in an effort to build Building and secure the profitable Silk Road , maintaining a variable military presence until the early 3rd century .

The Han–Xiongnu War , also known as the Sino-Xiongnu War , was a series of military battles fought Hostile_encounter between the Chinese Han Empire and the Xiongnu confederation from 133 BC to 89 AD .

Starting Process_start from Emperor Wu 's reign ( r. 141–87 BC ) , the Han empire changed Change from a relatively passive foreign policy to an offensive strategy to deal Resolve_problem with the increasing Xiongnu incursions on the northern frontier and also according to general imperial policy to expand Expansion the domain .

In 133 BC , the conflict escalated Cause_change_of_position_on_a_scale to a full-scale war Military_operation when the Xiongnu realized Coming_to_believe that the Han were about to ambush Attack their raiders at Mayi .

The Han court decided Deciding to deploy Arranging several military expeditions towards the regions situated Placing in the Ordos Loop , Hexi Corridor and Gobi Desert in a successful attempt to conquer Conquering it and expel Removing the Xiongnu .

As the situation deteriorated Change for the Xiongnu , civil conflicts befell and further weakened Cause_change_of_strength the confederation , which eventually splitted into two groups .

The Southern Xiongnu submitted Submitting_documents to the Han Empire , but the Northern Xiongnu continued to resist Defending and was eventually evicted Removing westwards by the further expeditions from Han Empire and its vassals , and the rise of Donghu states like Xianbei .

The Southern Xiongnu submitted Submitting_documents to the Han Empire , but the Northern Xiongnu continued to resist Defending and was eventually evicted Removing westwards by the further expeditions from Han Empire and its vassals , and the rise of Donghu states like Xianbei .

Marked Recording by significant events involving Cause_to_be_included the conquests over various smaller states for control Control and many large-scale battles , the war Military_operation resulted in Causation the total victory of the Han empire over the Xiongnu state in 89 AD .