When humans were still on the ladder of sub-consanguineous group marriage, there was no concept of "father", and children followed the matriarchal clan, so the clan was divided into generations according to the matriarchal clan line, which was called "matriarchal clan commune" or "matriarchal society". With the marriage entering monogamy, the children changed from paternal clan, so the matriarchal clan society gradually transitioned to paternal clan society. In ancient China, among ordinary clans, the members of the lowest generation had a common ancestor. That is, taxes and family names are composed of descendants of one of the ancestors of five generations or less, and family names are based on the totem or its name, character, number and name believed by this common ancestor. National chiefs (or chiefs, chiefs) are older and most prestigious living members. In barbaric times, clan leaders were usually the most powerful people; In civilized times, the patriarch is usually the person with the highest status. The patriarch has the right to preside over and lead the production, fighting, ancestor worship and punishment of the whole clan. When the sixth generation members come of age and hold ancestor worship ceremonies, because the ancestors of the highest ancestors only worship their ancestors until now (see the ancestor worship section of this book), clan members will naturally be divided into groups of different ancestors because of the number of the second generation ancestors, so that the original clan will be divided into several sub-clans according to the different ancestors of the sixth generation. If this is a new clan, because they have the closest blood relationship and the closest language, beliefs and customs, they naturally stay together in some activities (such as war). This kind of organization, which is more shoulder to shoulder than clan, is called "phratry".

Although the specific situation is more complicated, theoretically speaking, whenever a new clan is born, the old nation will develop into a phratry with several new clans. In this way, the original phratry has developed into a larger social organization including several new phratries. This higher-level organization than the phratry is a combination of several related phratries. If this consortium cooperates in a region for a long time, it will form a "tribe". In major military activities, tribes may also form alliances because of similarities in blood, language and beliefs, and then form a "tribal alliance." Tribes in a tribal alliance are related by blood with the same surname or by marriage with different surnames, and have a common military leader. This kind of group organization usually has the nature of nationality.