section_path: History/Western Han (202 BC – 9 AD)
section_name: Western Han (202 BC – 9 AD)
paragraph_text: Western Han (202 BC – 9 AD)
  
  China's first imperial dynasty was the Qin dynasty (221–207 BC). The Qin united the Chinese Warring States by conquest, but their regime became unstable after the death of the first emperor Qin Shi Huang. Within four years, the dynasty's authority had collapsed in a rebellion. Two former rebel leaders, Xiang Yu (d. 202 BC) of Chu and Liu Bang (d. 195 BC) of Han, engaged in a war to determine who would have hegemony over China, which had fissured into Eighteen Kingdoms, each claiming allegiance to either Xiang Yu or Liu Bang. Although Xiang Yu proved to be an effective commander, Liu Bang defeated him at the Battle of Gaixia (202 BC) in modern-day Anhui. Liu Bang assumed the title of Emperor at the urging of his followers and is known posthumously as Emperor Gaozu (r. 202–195 BC). Chang'an (modern Xi'an) was chosen as the new capital of the reunified empire under Han.
  
  At the beginning of the Western Han (traditional Chinese: 西漢; simplified Chinese: 西汉; pinyin: Xīhàn), also known as the Former Han (前漢; 前汉; Qiánhàn), thirteen centrally-controlled commanderies —including the capital region—existed in the western third of the empire, while the eastern two-thirds were divided into ten semi-autonomous kingdoms. To placate his prominent commanders from the war with Chu, Emperor Gaozu enfeoffed some of them as kings.
  
  By 196, the Han court had replaced all of these kings with royal Liu family members, with the lone exception of Changsha. The loyalty of non-relatives to the emperor was questioned, and after several insurrections by Han kings—with the largest being the Rebellion of the Seven States in 154—the imperial court began enacting a series of reforms that limited the power of these kingdoms in 145, dividing their former territories into new commanderies under central control. Kings were no longer able to appoint their own staff; this duty was assumed by the imperial court. Kings became nominal heads of their fiefs and collected a portion of tax revenues as their personal incomes. The kingdoms were never entirely abolished and existed throughout the remainder of Western and Eastern Han.
  
  To the north of China proper, the nomadic Xiongnu chieftain Modu Chanyu (r. 209–174 BC) conquered various tribes inhabiting the eastern portion of the Eurasian Steppe. By the end of his reign, he controlled the Inner Asian regions of Manchuria, Mongolia, and the Tarim Basin, subjugating over twenty states east of Samarkand. Emperor Gaozu was troubled about the abundant Han-manufactured iron weapons traded to the Xiongnu along the northern borders, and he established a trade embargo against the group.
  
  In retaliation, the Xiongnu invaded what is now Shanxi, where they defeated the Han forces at Baideng in 200 BC. After negotiations, the heqin agreement in 198 BC nominally held the leaders of the Xiongnu and the Han as equal partners in a royal marriage alliance, but the Han were forced to send large amounts of tribute items such as silk clothes, food, and wine to the Xiongnu.
  
  Despite the tribute and negotiation between Laoshang Chanyu (r. 174–160 BC) and Emperor Wen (r. 180–157 BC) to reopen border markets, many of the Chanyu 's subordinates chose not to obey the treaty and periodically raided Han territories south of the Great Wall for additional goods. In a court conference assembled by Emperor Wu (r. 141–87 BC) in 135 BC, the majority consensus of the ministers was to retain the heqin agreement. Emperor Wu accepted this, despite continuing Xiongnu raids.
  
  However, a court conference the following year convinced the majority that a limited engagement at Mayi involving the assassination of the Chanyu would throw the Xiongnu realm into chaos and benefit the Han. When this plot failed in 133 BC, Emperor Wu launched a series of massive military invasions into Xiongnu territory. The assault culminated in 119 BC at the Battle of Mobei, when Han commanders Huo Qubing (d. 117 BC) and Wei Qing (d. 106 BC) forced the Xiongnu court to flee north of the Gobi Desert, and Han forces reached as far north as Lake Baikal.
  
  After Wu's reign, Han forces continued to fight the Xiongnu. The Xiongnu leader Huhanye (r. 58–31 BC) finally submitted to the Han as a tributary vassal in 51 BC. Huhanye's rival claimant to the throne, Zhizhi Chanyu (r. 56–36 BC), was killed by Han forces under Chen Tang and Gan Yanshou (甘延壽) at the Battle of Zhizhi, in modern Taraz, Kazakhstan.
  
  In 121 BC, Han forces expelled the Xiongnu from a vast territory spanning the Hexi Corridor to Lop Nur. They repelled a joint Xiongnu- Qiang invasion of this northwestern territory in 111 BC. In that same year, the Han court established four new frontier commanderies in this region to consolidate their control: Jiuquan, Zhangyi, Dunhuang, and Wuwei. The majority of people on the frontier were soldiers. On occasion, the court forcibly moved peasant farmers to new frontier settlements, along with government-owned slaves and convicts who performed hard labour. The court also encouraged commoners, such as farmers, merchants, landowners, and hired labourers, to voluntarily migrate to the frontier.
  
  Even before the Han's expansion into Central Asia, diplomat Zhang Qian 's travels from 139 to 125 BC had established Chinese contacts with many surrounding civilizations. Zhang encountered Dayuan (Fergana), Kangju (Sogdiana), and Daxia (Bactria, formerly the Greco-Bactrian Kingdom); he also gathered information on Shendu (the Indus River valley) and Anxi (the Parthian Empire). All of these countries eventually received Han embassies. These connections marked the beginning of the Silk Road trade network that extended to the Roman Empire, bringing goods like Chinese silk and Roman glasswares between the two.
  
  From c. 115 BC until c. 60 BC, Han forces fought the Xiongnu over control of the oasis city-states in the Tarim Basin. The Han was eventually victorious and established the Protectorate of the Western Regions in 60 BC, which dealt with the region's defence and foreign affairs. The Han also expanded southward. The naval conquest of Nanyue in 111 BC expanded the Han realm into what are now modern Guangdong, Guangxi, and northern Vietnam. Yunnan was brought into the Han realm with the conquest of the Dian Kingdom in 109 BC, followed by parts of the Korean Peninsula with the Han conquest of Gojoseon and establishment of the Xuantu and Lelang commanderies in 108 BC. The first nationwide census in Chinese history was taken in 2 AD; the Han's total population was registered as comprising 57,671,400 individuals across 12,366,470 households.
  
  To pay for his military campaigns and colonial expansion, Emperor Wu nationalised several private industries. He created central government monopolies administered largely by former merchants. These monopolies included salt, iron, and liquor production, as well as bronze coinage. The liquor monopoly lasted only from 98 to 81 BC, and the salt and iron monopolies were eventually abolished in the early Eastern Han. The issuing of coinage remained a central government monopoly throughout the rest of the Han dynasty.
  
  The government monopolies were eventually repealed when a political faction known as the Reformists gained greater influence in the court. The Reformists opposed the Modernist faction that had dominated court politics in Emperor Wu's reign and during the subsequent regency of Huo Guang (d. 68 BC). The Modernists argued for an aggressive and expansionary foreign policy supported by revenues from heavy government intervention in the private economy. The Reformists, however, overturned these policies, favouring a cautious, non-expansionary approach to foreign policy, frugal budget reform, and lower tax-rates imposed on private entrepreneurs.