The Xiongnu were a confederacy of nomadic, pastoral peoples of the northern Chinese steppes, known in particular for their conflicts with the Han Dynasty.
Conflict between the Chinese and the Xiongnu is said to go back to the Qin Dynasty if not earlier; The First Emperor of Qin is said to have built the Great Wall chiefly as a defensive measure against the Xiongnu, and to have sent out military expeditions to fight them. Though typically presented as "barbarians," and as first and foremost a threat to be defended against, from the Xiongnu point of view, we can also see how they might have perceived Qin, and later Han, actions as offensive attacks upon their livelihoods. The Great Wall, though cited as a defensive measure, also (quite possibly intentionally) cut off the Xiongnu from much of their traditional grazing lands. Thus, it has been argued, the Xiongnu had good reason to attack the Wall, in order to regain prime pastures for their flocks, of which they had been deprived.
One Xiongnu leader by the name of Maodun is particularly known for his strength. Becoming leader of the confederacy around 209 BCE, he launched raids which ultimately forced the Han to pay tribute, in the form of luxury goods and high-born maidens, to the Xiongnu in exchange for peace. At one point, Maodun is said to have been so self-assured as to demand the empress dowager, widow of Emperor Gaozu of Han, as his wife. She replied that she was too old and ugly to marry anyone, and managed to resist Maodun's demands.
The Xiongnu are said to have had military advantages over the Han in several respects, beginning with the fact that as a nomadic people, they had no established cities to attack, and were constantly on the move, making them sometimes difficult for the Han armies to find. Further, Xiongnu were well-accustomed to equestrian life, and the military skills employed in their raids were in a sense merely extensions of the same skills they used every day in tending their flocks; this, in contrast to a Han soldier who had to be taken away from his agricultural life and work, and specially trained in the very separate arts of war.
Early Han leaders took a policy of appeasement of the Xiongnu, paying them gifts and wives; such payoffs were quite expensive, perhaps amounting to as much as 7% of the government's total revenues. Han Wudi, however, ended that policy, instead launching large military expeditions against the Xiongnu. He established military colonies in many areas of the border, and made captured territory into tributary states, making the local leaders send their sons to the Han capital as hostages. He paid for these efforts by dramatically expanding government revenues through official monopolies on iron, salt, liquor, and the minting of coins.
Ultimately, Han military efforts were successful in breaking the power of the Xiongnu. By 53 BCE, the confederacy split into two factions, with a southern federation serving as tributary to the Han, opposed by the northern federation.
- Conrad Schirokauer, et al, A Brief History of Chinese and Japanese Civilizations, Fourth Edition, Cengage Learning (2012), 55-57.