During the Wei 曹魏 (220-265), Jin 晉 (265-420) and Southern and Northern Dynasties 南北朝 (300~600) periods, a class of wealthy landowners dominated society and had also access to political power. These eminent families were known with the terms daxing 大姓, dazu 大族, fayue 閥閱, gaomen 高門, haomen 豪門, haoqiang 豪強, haozu 豪族, shijia 世家, menfa 門閥, mingshi 名士, shizu 士族, shizu 世族, shizu 勢族, wangzu 望族, youxing 右姓 or zhuxing 著姓.
The phenomenon of land accumulation in the hands of a few wealthy families emerged during the Later Han period 後漢 (25-220 CE). Free peasants were for several reasons – natural disasters, indebtedness, war – forced to transfer rights over their own land to local magnates and became tenant farmers, in the worst case, serfs (nuke 奴客). They had to pay rent and to deliver various services, but obtained protection and were free from the obligation to pay taxes. Seen from the viewpoint of the state, this phenomenon was two-sided. On the one hand, the decreasing number of free peasants reduced the number of taxpayers, but on the other, the magnates took over administrative duties over local societies which the state was not able to guarantee in a time of social and political unrest.
The estates of magnates were called zhuangyuan 莊園 or zhuangtian 莊田.
Members of eminent families were entitled to take over state offices. The rank of offices such families could obtain depended on the classification of the family itself. This classification was realized according to a nine-rank system (jiupin zhongzheng zhi 九品中正制) introduced in the early 3rd century. Members of class-1 or -2 families were appointed to high state offices, such of rank 9 to low offices in the central or local administration.
Internally, the position of each family member was determined by the distance to the main lineage (zongzu 宗族) of the family cluster ("clan"). Members of the main line (shizu 士族), entitled to occupy higher positions in the hierarchy of state offices, were also called "pure officials" (qingguan 清官), while those of lateral lines (shuzu 庶族) could only obtain "murky offices" (zhuoguan 濁官). This rule was summarized in the saying "In high-ranking offices, no poor people are found, and lower ranks are never occupied by people of eminent families." (Shangpin wu hanmen, xiapin wu shizu 上品無寒門，下品無世族).
Eminent family clusters dominated whole commanderies and were therefore referred to by the location, like the Zhengs from Rongyang 榮陽鄭氏, the Xus from Yingchuan 潁川荀氏, the Lus from Wujun 吳郡陸氏, the Wangs from Langya 琅琊王氏, the Xies from Chenjun 陳郡謝氏, the Xiaos from Lanling 蘭陵蕭氏, or the Lis from Longxi 隴西李氏.
The rank of individual families (status, mendi 門第) also determined the number of "client family members" (yinzu 蔭族), "client peasants" (yinke 蔭客) and "client households" (yinhu 蔭戶) the family was allowed to take under their wings. Clients did not have to pay taxes or deliver corvée (yaoyi 徭役) to the government. The higher the rank, the more clients were allowed. The rank had also an influence of the size of fields families were allowed to possess, at least in theory. In practice, the "field occupation system" (zhantian zhi 占田制) expressed the size of fields a household of a certain rank should ideally possess. The tax in grain was also fixed according to the rank of the family (ketian zhi 課田制).
Finally, the rank determined social relations. Members of high families were not allowed to marry such of lower rank or to carry out certain ceremonies together, not to speak of poor people (hanmen 寒門). These rules were a strict intensification of the Confucian separation between different social ranks. Even if these ranks were, once bestowed, hereditary, the position of individual families could change over time.
The hereditary character of family status can already be seen in some genealogies of the Eastern Han period: Yang Zhen 楊震 (d. 124) and his descendants, the Yangs from Hongnong 弘農楊氏, were granted the title of Duke three times in four generations, and among the Yuans from Runan 汝南袁氏, a family founded by Yuan An 袁安 (d. 92), five persons were made dukes in just four generations.
The eminent families did not only have political, social and economic influence, but were the carriers of thought and literature. Most writers and thinkers of the Jin and Southern Dynasties periods 南朝 (420-589), for instance, the protagonists of the stories in the collection Shishuo xinyu 世說新語, were scions of eminent families. Young males were usually appointed to posts in which they served as attendants or secretaries of higher officials, and rose to better positions after reaching maturity. After several generations, the privileges granted to members of eminent families were often exploited, while they ceased to care for their duties. A proverb from the Eastern Jin period 東晉 (317-420) brings it to the point: "Taking office, they do not care for official matters, and in managing affairs, they have no sense for executing matters." (Ju guan wu guan [verb] guan zhi shi, chu shi wu shi [verb] shi zhi xin 居官無官官之事，處事無事事之心).
From the fifth century on, the rigorous regulation of access to state offices was softened, and also members of "cold-gate" families (hanmen) could achieve high positions at the court.
In north China, the situation was also different. In the course of the fourth century, numerous eminent families had fled to the southeast. Those remaining in the north did not play political roles in the turbulent political landscape of the Sixteen States 十六國 (300~430). After the unification of the north by the Northern Wei dynasty 北魏 (386-534), a new nobility rose to power, namely the leaders of various Xianbei 鮮卑 tribes. Just eight families rose to prominence and became new "eminent families" in north China.
The Sui 隋 (581-618) and Tang 唐 (618-907) dynasties had officially abolished the nine-rank system for the classification of families, yet traces of this system remained in family registers like the Yuanhe xingzuan 元和姓纂. These registers were arranged according to the status of families.