Qin Shi Huang (秦始皇) (259 BC – 210 BC), personal name Ying Zheng (嬴政), was king of the Chinese State of Qin from 246 BC to 221 BC during the Warring States Period. He became the first emperor of a unified China in 221 BC. He ruled until his death in 210 BC at the age of 49.

Calling himself the First Emperor (Chinese: 始皇帝) after China's unification, Qin Shi Huang is a pivotal figure in Chinese history, ushering nearly two millennia of imperial rule. After unifying China, he and his chief advisor Li Si passed a series of major economic and political reforms. He undertook gigantic projects, including building and unifying various sections of the Great Wall of China, the now famous city-sized mausoleum guarded by a life-sized Terracotta Army, and a massive national road system, all at the expense of numerous lives. To ensure stability, Qin Shi Huang outlawed and burned many books and buried some scholars alive.

From the beginning of the Zhou dynasty in 1045 BC to the time of the First Emperor, rulers of the Chinese states were titled Wang (Chinese: 王), a term that originally meant "big man" but later came to mean "chief" or "king". Following his defeat of the last of the Warring States in 221 BC, King Zheng of Qin became de facto ruler of all China. To celebrate this achievement and consolidate his power base, King Zheng created a new title calling himself the First Sovereign Emperor of Qin (Chinese: 秦始皇帝; pinyin: Qín Shǐ Huángdì; Wade–Giles: Ch'in Shih Huang-ti), often shortened to Qin Shi Huang (Chinese: 秦始皇; pinyin: Qín Shǐ Huáng; Wade–Giles: Ch'in Shih-Huang).

The Emperor of China (Chinese: 皇帝; pinyin: Huángdì, pronounced [xu̯ɑ̌ŋ tî]) refers to any sovereign of Imperial China reigning between the founding of Qin Dynasty of China, united by the King of Qin in 221 BCE, and the fall of Yuan Shikai's Empire of China in 1916. When referred to as the Son of Heaven (Chinese: 天子; pinyin: tiānzǐ, pronounced [ti̯ɛ́n tsɨ̀]), a title that predates the Qin unification, the Emperor was recognized as the ruler of "All under heaven" (i.e., the world). In practice not every Emperor held supreme power, though this was most often the case.^{[citation needed]}

Emperors from the same family are generally classified in historical periods known as Dynasties. Most of China's imperial rulers have commonly been considered members of the Han ethnicity, although recent scholarship tends to be wary of applying current ethnic categories to historical situations. During the Yuan and Qing dynasties China was ruled by ethnic Mongols and Manchus respectively after being conquered by them. The orthodox historical view over the years sees these as non-native dynasties that were sinicized over time, though some more recent scholars argue that the interaction between politics and ethnicity was far more complex. Nevertheless, in both cases these rulers had claimed the Mandate of Heaven to assume the role of traditional emperors in order to rule over China proper.