During the period of the Eastern Jin, the Sixteen States, the Southern dynasties, and the Northern dynasties, population movement caused the conflicts both between the Han and minorities in the north and immigrants and natives in the south. The traditional method of estimating the immigrants was based on the households of migration prefectures, subprefectures and counties recorded in local gazetteers, which is actually different between the actual distribution of immigrants and those registered in local gazetteers. Thus, the migration population and their descendents need to be recalculated. In fact, migrations in the Sixteen States were largely for military and agriculture purposes, while in the Northern dynasties, particularly the Northern Wei, population movements were mostly to fill the capitals, the boundary and inland areas, both were enforced by the governments. Population migration often determined government policies, enriched cultural contents, promoted economic developments, and changed the intellectual trends and social structure in certain dynasties, especially in the Eastern Jin and the Southern dynasties.