Jin Dynasty was the only period, which unified the country during the period between the Wei, the Jin and the Southern and Northern Dynasties (420 - 589), though this kind of achievement was not lasting.

Although Jin Dynasty was short and full of conflicts, the mix between nationalities was accelerated through the long-term contacts and mutual influences.

Western Jin Dynasty (265-316)

Caopi established the Wei Kingdom with the support from General Sima Yi. During the whole Wei period, Sima family totally assisted three out of five kings of the Wei Kingdom. Gradually, they gained the control of the executive and military powers of the kingdom. After Sima Yi death, his two sons became, one after the other, the dominant men of the kingdom.

In 265 AD, Sima Yan, the grandson of Sima Yi, deposed the emperor of Wei and established his own regime Jin, making Luoyang his capital city. Historically the dynasty is known as the "Western Jin Dynasty" and Sima Yan was known as Emperor Wu. In 280 AD, the Western Jin wiped out the Wu, the last surviving regime of the Three Kingdoms Period (220 - 265) and reunified the south and north.

Emperor Wu conferred dukedoms to many of his kinsmen due to their contributions in the founding and consolidation of the empire. Since the Jin was based on the power of hereditary aristocrats, measures were taken to protect the interests of the privileged, which further fed up of the big family. And consequently, conflicts between the aristocratic families increased. They contested with each in the accumulation of wealth and the enjoyment of the luxurious life. Thus the power of the Jin imperial government was seriously impaired.

Meanwhile, the struggle for power intensified in the imperial court. From 291 onwards, eight dukes of the royal family stirred up a series of wars against each other. These wars lasted 16 years, greatly dislocating the social economy and weakening the empire power.

After the disturbances, the country was deep in chaos. In 308, Liuyuan, the chief of the Xiongnu tribe, crowned himself the king of Han. His army captured Luoyang, the capital of the Western Jin Dynasty and caught the emperor. As the survivals of the Jin made another emperor in Chang'an (present Xi'an), the Xiongnu army broke into Chang'an in 316 and put an end to the Western Jin Dynasty.

The Western Jin Dynasty ruled fifty-one years with four emperors on the throne. After it, China went into another troubled period of disunity for 272 years.

Eastern Jin Dynasty (317 - 420)

Political History
After the collapse of the Western Jin Dynasty (265 - 316), the Han government retreated to the east of the Yangtze River. In 317, Sima Rui, a member of the Jin royal family stationed in Jiankang (present city of Nanjing in Jiangsu Province), re-established Jin supremacy, through what has become known as the Eastern Jin Dynasty (317 - 420). Eastern Jin Dynasty had lasted for 103 years with eleven emperors over fourteen generations until it was substituted by the Song Dynasty founded in 420.

In the Eastern Jin period, the development of powerful family politics reached its peak as royal power was on the decline. Some noble families, by right of their contribution to the foundation and consolidation of the Jin, then led a life of luxury and privilege. Born from different regional and cultural background, they struggled and supplanted each other. During the over one-hundred-year reign of the Eastern Jin, noble families from the Central Plains was in a dominant situation, in which Wang, Xie, Yu and Huan families even determined the state affairs.

Actually, the eastern Jin only controlled the area south of the Yangtze River, leaving the North China occupied by other minorities. During the period from the beginning of the fourth century to the first part of the fifth century, many ethnic groups founded their states in this area. Historically, fifteen major of these states in the north, together with the Kingdom of Chenghan in the southwest area, were called "the Sixteen States".

The sixteen states never stopped fighting against each other: On the one hand, wars and conflicts destroyed the economy in the northern areas and on the other hand, the mix between nationalities was accelerated through the long term contacts and mutual influences.

Situated in the south area of the Yangtze River, Jin emperors never gave up the efforts to reoccupy the North China. Zudi, a southern gentry-official, once led a northern expedition and regained the Yellow River Valley for a short time. Afterwards, noble family in power repeatedly advocated northern expeditions so as to enhance their prestige. They once take Luoyang, entered Central Shaanxi Plain and approached Hebei. However, these triumphs were all short-lived for the counterattack by the minorities.

In the late part of the fourth century, Qianqin (Former Qin) was set up by the Di minority and reunified the Yellow River Valley. The Emperor Fujian endeavored to develop economy and made his state stronger.

In 383 AD, despite the objection from all social groups, Fujian drafted soldiers from all nationalities to launch a war against the Eastern Jin. Xie'an, the Prime Minister of the Eastern Jin, offered resistance and sent Xieshi and Xiexuan to fight against the attack. Finally Eastern Jin won in a decisive battle along Feishui River, putting an end to the war. After the battle of Feishui River, Qianqin State collapsed quickly and the Eastern Jin had, by that time, the chance to reoccupy many areas.

However, the dispelling of the external threat was followed by a series of internal disturbances. First, Sun'en and Luxun launched rebellions. Then Huanxuan won the civil war and usurped the throne. Later, General Liuyu of the Beifu troops suppressed the peasant uprisings and, relying on his prestige gained through northern expeditions, established his own state to replace the Eastern Jin.

Eastern Jin Dynasty was gone while the disunion continued. China entered another divisive age the Northern and Southern Dynasties.

Economy

During the Eastern Jin Dynasty, the noble families devoted themselves to the economic development. Due to the incessant wars in North China, peasants gradually migrated into the area south of the Yangtze River in pursuit of peaceful life. The migration not only reinforced the manpower in these areas, but brought in advanced productive implements and techniques. In addition, there are so many rivers in the area south of the Yangtze River, providing a good irrigating condition to the agricultural production. All said factors contributed a lot to the progress of agriculture.

Also, people from the north brought improvement in handicraft industry. Commerce also got its progress in this period. Jiankang, the capital city of the Eastern Jin became the largest businesses city in the area south of the Yangtze River. In addition, the economic center began to move to the Yangtze River Valley from the Yellow River Valley.

Five Hus and Sixteen States

From the end of the Western Jin (215 - 316) to the Northern Wei, five minorities once founded their states in the North China. They were called by a joint name "Five Hus and Sixteen States".

Five Hus: means five ethnic minorities that live in north china, namely Xiongnu, Xianbei, Qiang, Jie and Di.

Sixteen States: include Qianliang (Former Liang), Houliang (Latter Liang), Nanliang (Southern Liang), Xiliang (Western Liang), Beiliang (Northern Liang), Qianzhao (Former Zhao), Houzhao (Latter Zhao), Qianqin (Former Qin), Houqin (Latter Qin), Xiqin (Western Qin), Qianyan (Former Yan), Houyan (Latter Yan), Nanyan (Southern Yan), Beiyan (Northern Yan), Xia and Chenghan.