Modu (Mòdùn) kills his father Touman and becomes chanyu, catalyzing the consolidation of Xiongnu power into a steppe confederation that soon becomes the Han dynasty’s primary northern rival.
The Xiongnu campaign against the Donghu confederation strengthens Modu’s position and expands Xiongnu dominance in eastern Inner Asia, helping stabilize the confederation’s frontiers before intensified pressure on Han borderlands.
At Mount Baideng (near modern Datong), Modu’s forces trap Han founder Liu Bang (Emperor Gaozu). The episode underscores Han vulnerability to steppe cavalry warfare and pushes Han policy toward negotiated settlement.
After early defeats, the Han adopt heqin (marriage alliance plus gifts/tribute) as a state policy to reduce raids and manage relations with the Xiongnu through diplomacy rather than decisive frontier war.
Xiongnu victory over the Yuezhi helps secure Xiongnu control over the strategic Hexi Corridor region, shaping the later Han drive to break Xiongnu influence over routes linking China to Central Asia.
The failed Mayi ambush ends the de jure peace and marks a turning point toward open conflict. It also drives Han reforms emphasizing cavalry and deep-penetration campaigns against Xiongnu power.
Sent in 138 BCE to seek alliances in Central Asia, Zhang Qian is captured by the Xiongnu for about a decade but ultimately returns with intelligence that reshapes Han strategy in the Western Regions and undermines Xiongnu monopoly over trans-Inner Asian contacts.
Han general Huo Qubing’s 121 BCE offensives inflict major defeats and trigger high-profile Xiongnu surrenders in the Hexi region, paving the way for Han frontier consolidation and greater access to Central Asian routes.
In a major winter–spring offensive, Han forces under Wei Qing and Huo Qubing strike deep into Xiongnu territory and win at Mobei, accelerating the shift of Xiongnu power north of the Gobi and reducing pressure on the Han heartland.
The Han organize the newly secured Hexi Corridor into commanderies (Wuwei, Zhangye, Jiuquan, Dunhuang), institutionalizing garrisons and settlement that both protects the frontier and supports Silk Road-era movement through the corridor.
The Han establish the Protectorate of the Western Regions (with a protector-general) to manage garrisons and allied states in the Tarim Basin area, a strategic move that contests Xiongnu influence over the Western Regions and long-distance trade corridors.
By the mid-1st century CE, the Xiongnu divide into Northern and Southern groupings; the Southern Xiongnu align with Han authority, reshaping the conflict into a Han–Southern Xiongnu partnership against northern steppe rivals.
Han general Dou Xian leads a major expedition that defeats the Northern Xiongnu near the Altai Mountains. The victory—achieved with allied forces including Southern Xiongnu—cripples Northern Xiongnu power and prompts flight and surrenders.
Xiongnu Confederation and Han–Xiongnu Conflicts (c. 3rd century BCE–89 CE)
