Although formally "The Son of Heaven," the power of the emperor varied between different emperors and different dynasties, with some emperors being absolute rulers and others being figureheads with actual power in the hands of court factions, eunuchs, the bureaucracy or noble families.
The title of emperor was usually transmitted from father to son. Most often, the first-born son of the empress inherited the office, failing which the post was taken up by the first-born son of a concubine or consort of lower rank, but this rule was not universal and disputed succession was the cause of a number of civil wars. Unlike in Japan, traditional Chinese political theory allowed for a change in dynasty, and an emperor could be replaced by a rebel leader. This was because a successful rebel leader was believed to enjoy the mandate of heaven, while the deposed or defeated emperor had lost favour with the gods, and his mandate was over, a fact made apparent to all by his defeat.
It was generally not possible for a female to succeed to the throne, so that in history of China there has only been one reigning empress, the Empress Wu, whose reign punctuated the Tang dynasty. However, there have been numerous cases in Chinese history where a woman was the actual power behind the imperial throne (see éminence grise).
The social system of the Zhou Dynasty is sometimes referred to as the Chinese proto-feudalism and was the combination of Fengjian (Honours and Awards) and Zongfa (Clan Law). Male aristocracies were classified into, in descending order of rank:
Fengjian (Honours and Awards) divided the noble class further into (originally) five ranks. The sizes of troops and domains a male noble would command would be determined by his rank of peerage:
While before the Han Dynasty a peer with a place name in his title actually governed that place, it had only been nominally true since. Any male member of the nobility or gentry could be called a gongzi (公子 gōng zǐ) (or wangzi (王子 wáng zǐ) if he is a son of a king, i.e. prince).
Zongfa (宗法, Clan Law), which applied to all social classes, governed the primogeniture of rank and succession of other siblings. The eldest son of the consort would inherit the title and retained the same rank within the system. Other sons from the consort, concubines and mistresses would be given titles one rank lower than their father.
As time went by, all terms had lost their original meanings nonetheless. Qing (卿), Daifu (大夫) and Shi (士) became synonyms of court officials. Physicians were often called Daifu during the Late Imperial China. Referring to a male or self-reference of a male as Gongzi eventually became a way to raise one's mianzi (refer to Face (social concept)), and would indeed be considered flattery today.
The founder of the Han Dynasty, Liu Bang, continued to use the title Huangdi. In order to appease his wartime allies, he gave each of them a piece of land as their own "kingdom" (Wangguo) along with a title of Wang. He eventually killed all of them and replaced them with members of his family. These kingdoms remained effectively independent until the Rebellion of the Seven States. Since then, Wang became merely the highest hereditary title, which roughly corresponded to the title of prince, and, as such, was commonly given to relatives of the emperor. The title Gong also reverted purely to a peerage title, ranking below Wang. Those who bore such titles were entirely under the auspices of the emperor, and had no ruling power of their own. The two characters combined to form the rank, Wanggong, grew to become synonymous with all higher court officials.
During the Tang dynasty, nobles lost most of their power to the mandarins when imperial examination replaced the nine-rank system.
Subsequent dynasties expanded the hereditary titles further. It should be noted, however, that not all titles of peerage are hereditary, and the right to continue the heredity passage of a very high title was seen as a very high honour; at the end of the Qing dynasty, there were five grades of princes, amongst a myriad of other titles. For details, see Qing Dynasty nobility.
A few Chinese families enjoyed hereditary titles in the full sense, the chief among them being the Holy Duke of Yen (the descendant of Confucius); others, such as the lineal descendants of Wen Tianxiang, ennobled the Duke of Xingguo, not choosing to use their hereditary title. The Imperial Clansmen consisted of those who trace their descent direct from the founder of the Qing dynasty, and were distinguished by the privilege of wearing a yellow girdle; collateral relatives of the imperial house wore a red girdle. Twelve degrees of nobility (in a descending scale as one generation succeeds another) were conferred on the descendants of every emperor; in the thirteenth generation the descendants of emperors were merged in the general population, save that they retain the yellow girdle. The heads of eight houses, the Iron-capped (or helmeted) princes, maintained their titles in perpetuity by rule of primogeniture in virtue of having helped the Manchu conquest of China.
All titles of nobility were officially abolished when China became a republic in 1912. They were briefly revived under Yuan Shikai's empire and after Zhang Xun's coup. The last emperor was allowed to keep his title but was treated as a foreign monarch until the 1924 coup. Manchukuo also had titles of nobility.
In modern Chinese, a king is referred to as a Wang, while an emperor would be referred to as Huangdi. The king in those times were referred to as the mandate of heaven. Therefore Victoria of the United Kingdom was styled Nü-Wang (Queen) of the United Kingdom of Great Britain and Ireland, and Nü-Huang (Empress) of India.