Northern and Southern Dynasty

The Southern and Northern Dynasties period was a period of disunity in Chinese history.
General Liu Yu of Eastern Jin dynasty founded his dynasty Song Dynasty to replace the Eastern Jin in 420. It marked the beginning of Southern Dynasty. When Liu Yu founded his Song dynasty in southern part of China, an ethnic minority the Tuoba clan of the Xianbei tribe rose from the north. They set up the Northern Wei in 386 and unified the north in 439. It marked the beginning of the Northern Dynasty, than Chinese history entered an era of separation and confrontation between the south and the north.

In the south, there were four different successive regimes: the Song, the Southern Qi, the Liang and the Chen. All emperors made Jiankang (now Nanjing in Jiangsu) their capital, except Emperor Yuan of Liang who made Jiangling his capital for three years. Of these regimes, the Song (420-479) founded by Liu was the largest, strongest, and most long-lived, ruled by eight emperors of four generations. Lasting for only 23 years from 479 to 502, the Southern Qi had seven emperors of three generations because of frequent wars. The Liang extended from 502 to 557, ruled by four emperors of three generations, among whom Emperor Wu enjoyed the longest reign for 48 years. The Chen lasted 33 years from 557 to 589, with five emperors of three generations. It was a small and weak regime with a small population. Besides, the Chen rulers were quite corrupt. Finally, the Chen was conquered by the powerful enemies Sui Dynasty from the north. The Song, the Qi, the Liang, and the Chen are historically known as the Southern Dynasties.
 
The Southern Dynasties saw the decline of power and influence of powerful families and gentry-lords. Due to the strengthened royal power, the powerful families and gentry-lords, despite their high social status, could no longer dominate the court. Meanwhile, further development of the area south of the Yangtze River gave the local people opportunities to rise in power, to enter the government and even to serve the emperor. Beginning at the time of the Xiao Liang and the Chen, the southern landlords also became influential local powers.
After Emperor Xiaowen of Northern Wei Dynasty ascended to the throne, he removed the capital to Luoyang and vigorously promoted the learning of the Han culture. The Northern Wei lasted over a century, with 12 emperors of nine generations. It had relatively greater influence on the history of the Southern and Northern Dynasties.

At the beginning, the Northern Wei practised the "Suzerain check and protection" system. They neatened the administration of officials, strengthened the local rule and facilitated the stability of country. In 494, Northern Wei moved capital to Luoyang, Emperor Xiaowendi promulgated a decree to implement the land equalization system, took measures to reform traditional Xianbei customs. He ordered all the Xianbei people wear the same clothes as the Han people, Han language to be used in the court and encouraged intermarriage between the Xianbei and Han people, persuaded the Xianbei people to be used the surname of Han people and stipulated different statuses for Xianbei nobilities. The removal of capital and reforms of administrative system facilitated the development of Northern Wei’s economy, strengthened its reign, and facilitated the amalgamation between the Xianbei and Han people, leading Northern Wei to great prosperity. But, these reforms invited strong opposition from certain conservation aristocrats and Xianbei military man. In 523, six towns rose to rebel. The Northern Wei was disunity and plunged into civil war.

In the final years Northern Wei reign, two powerful ministers, Gao Huan and Yuwen Tai, split the Northern Wei into the eastern and western parts. The Eastern Wei (534-550) had one emperor ruling for 16 years, with Yecheng as its capital. The Western Wei (535-556) had a history of 22 years, ruled by three emperors with Chang'an as its capital. These two states were later replaced by the Northern Qi (550-577) and the Northern Zhou (557-581) respectively. In 577, the Northern Zhou ended the Northern Qi and the north China got reunified. In 581, Yang Jian, a family member of Northern Zhou's empress usurped the throne and changed the name to the Sui. In history, the five dynasties in the north of Cnina - the Northern Wei, the Eastern Wei, the Western Wei, the Northern Qi, and the Northern Zhou were called the Northern Dynasties.

And historians referred to this period when the Southern Dynasties and the Northern Dynasties co-existed as the Southern and Northern Dynasties.