According to the historical characteristics of Wei, Jin, Southern and Northern Dynasties, what are the favorable conditions for the reunification of Sui Dynasty?

1. Politically, regime changes frequently. After the end of the Eastern Han Dynasty, the three kingdoms of Wei, Shu and Wu first appeared, followed by the brief reunification of the Western Jin Dynasty and the local security of the Eastern Jin Dynasty. When the Eastern Jin Dynasty was partial to security, there were five lakes and sixteen countries established by ethnic minorities in the north, and finally the Northern Wei Dynasty unified the north. After the end of the Northern Wei Dynasty, it was the Northern Qi Dynasty and the Northern Zhou Dynasty. After the disintegration of the Eastern Jin Dynasty, Qi Liangchen was established in the Southern Song Dynasty.

2. As far as class relations and class structure are concerned, the clan gate system was formed in the Wei and Jin Dynasties. This system has a great influence on national politics. The clan has mastered the political power, blocking the way for the cold people to enter the political power. Later, it led to political darkness and political turmoil. The formation of the gate system strengthened the personal attachment of farmers to landlords, resulting in the tenant system and multi-party system.

3. Economically, the system of reclaiming land, occupying land and equalizing land appeared successively, among which the latter two systems appeared for the first time in the history of China, and these systems played different roles in promoting economic development in the history of China. In addition, during the Wei, Jin, Southern and Northern Dynasties, the south was further developed and the economic center of gravity moved south.

4. In ethnic relations, a large number of ethnic minorities in the north moved inward and a large number of ethnic minorities in the Central Plains moved south, which led to the great migration and integration of ethnic groups since the Spring and Autumn Period and the Warring States Period and played an important role in the history of the formation and development of the Chinese nation.

5. Ideological and cultural aspects: the situation of Confucianism's exclusive respect has been broken, metaphysics has risen, Buddhism and Taoism have developed, and the pre-Qin philosophers' theories have been "revived" to varying degrees, which is another ideological emancipation movement in the ancient cultural history of China; Great achievements have also been made in history, literature, art and science and technology.

The favorable conditions caused by

(1) Great integration of northern nationalities.

② Economic development in the south of the Yangtze River.

The people of North and South yearn for reunification.

Emperor Wendi of Sui Dynasty took the elimination of Chen's reunification as the primary task and made great efforts to reform, which made the national strength rise rapidly.

In the Southern Dynasties, Chen's national strength was weak, his politics was corrupt and his class contradictions were sharp.