

Huangdi (皇帝), a title created by Zheng 政, First Emperor of Qin 秦始皇帝 (literally the First Huangdi of the Qin) in reference to the legends of the Three August Ones (Huang) and the Five Emperors (Di), and thereafter employed by all who claimed the "Mandate of Heaven" over all or part of China, until 1912 when the last Huangdi Puyi 溥儀, the Last Emperor of Qing Dynasty of Qing Dynasty was forced to abdicate.
That the European title Emperor (or Imperator, Kaiser, etc.) comes to be associated with Huangdi in terms of translating between Chinese and Western languages is primarily a matter of convenience. A number of rulers of the Warring States period, officially titled Gong (公 rendered "Duke"), and later Wang (王 "King"), were more powerful than some of the later Huangdi. Nonetheless, we shall restrict this project to those who formally assumed the title of Huangdi in their lifetime, including the deposed and "puppets", but excluding the father, grandfather, etc. of the founding Emperor who were customarily bestowed the title of Huangdi posthumously.
The European term "dynasty" may also be misleading when used in the Chinese context. It does correctly describe a paternal line of monarchs, but a change of dynasty in China would typically involve a violent overturn of the ruling family, either in an all-out war or a coup. Often It would also be associated with an institutional change, sometimes more drastic than others, and is therefore used to demarcate a new era. When someone is referred to as a man of Tang dynasty (in English), it simply means he lived in the period of Tang dynasty, not to suggest that he was a member of the imperial family.
In more than two millennia of continuous existence, there was only one female Huangdi (Empress regnant), Wǔ Zétiān 武則天, though about a dozen others have had near absolute control of power in the name of Empress Consort (皇后) or Empress Dowager (皇太后).
The longest reign is that of Kangxi Emperor of Qing China 清康熙帝, reaching its 61st year. His grandson, Qianlong Emperor of Qing China 清乾隆帝, in his 60th year opted to abdicate the throne to his son, but continued to rule for three more years as Tai Shang Huangdi (Grand Emperor, or Emperor emeritus). The majority of Huangdi, however, died at young age in time of political instability.
The conventional dictionary with European nobility is summarized here:
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The following is a list of important Emperors to help you navigate through Geni. For the full list click "View all" on the Profiles module on the right
Zheng 政, First Emperor of Qin 秦始皇帝
Liu Bang 劉邦, Emperor Gaozu of Han
Wang Mang 王莽, Emperor of Xin Dynasty
Liu Xiu 劉秀, Emperor Guangwu of Han
Liu Bei 劉備, Emperor of Shu-Han
Sima Yan 司馬炎, Emperor Wu of Jin
See album of official portraits
Zhao Kuangyin 趙匡胤, Emperor Taizu of Song
Zhao Gou 趙構, Emperor Gaozong of Song
Zhao Shen 趙昚, Emperor Xiaozong of the Song
Zhao Yun 趙昀, Emperor Lizong of the Song
Aguda 阿骨打, Emperor Taizu of Jin (Jurchen)
Genghis Khan of the Mongol Empire