The Warring States Period (simplified Chinese: 战国时代; traditional Chinese: 戰國時代; pinyin: Zhànguó Shídài), also known as the Era of Warring States, or the Warring Kingdoms period, covers the Iron Age period from either 476 BC or 453 BC to the reunification of China under the Qin Dynasty in 221 BC. It is considered to be the second part of the Eastern Zhou Dynasty, following the Spring and Autumn Period, although the Zhou Dynasty ended in 256 BC, 35 years earlier than the end of the Warring States period. During these periods, the Chinese sovereign (king of the Zhou Dynasty) was merely a figurehead.

The name Warring States Period was derived from the Record of the Warring States, a work compiled early in the Han Dynasty. The date for the beginning of the Warring States Period is disputed. While it is frequently cited as 475 BC (following the Spring and Autumn Period), 403 BC, the date of the tripartite Partition of Jin, is also considered as the beginning of the period.^{[citation needed]}

The political geography of the era was dominated by the Seven Warring States, namely:

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.