The supreme ruler of imperial China was called huangdi, meaning “emperor.” The origin of this word is a legend of ancient sovereigns known as the three huang ( 皇 sovereigns) and five di (帝 emperors). It is said that the three huang were Fuxi, Shennong and Suiren, while others identify them as Fuxi, Shennong and Nüwa. The five di are usually said to be Huangdi, Zhuanxu, Ku, Yao and Shun. In fact, they were just leaders of tribes or tribal alliances in remote antiquity. As they had unique contributions (Fuxi, for instance, taught people hunting and fishing and created the eight trigrams), they were honored with the titles huang or di. Huang originally meant august and great, and di indicated shrewdness and alertness. After Ying Zheng(259-210 BC), the king of Qin, unified China, he viewed his achievements as being greater than those of the three huang and five di. Therefore he put huang and di together and called himself “ the First Huangdi (Emperor).” From then on, huangdi became the title of the highest ruler in China.

As soon as he unified the whole country,Ying Zheng, King of the State of Qin, called himself Huangdi (emperor) because he believed his accomplishments were far greater than those of the three huang and five di. (History as a Mirror)