Jin dynasty (266–420) in the context of "Emperor Hui of Jin"

The Three Kingdoms of Cao Wei, Shu Han, and Eastern Wu dominated China from AD 220 to 280 following the end of the Han dynasty. This period was preceded by the Eastern Han dynasty and followed by the Western Jin dynasty. Academically, the periodisation begins with the establishment of Cao Wei in 220 and ends with the conquest of Wu by Jin in 280. The period immediately preceding the Three Kingdoms, from 184 to 220, was marked by chaotic infighting among warlords across China as Han authority collapsed. The period from 220 to 263 was marked by a comparatively stable arrangement between Cao Wei, Shu Han, and Eastern Wu. This stability broke down with the conquest of Shu by Wei in 263, followed by the usurpation of Cao Wei by Jin in 266 and ultimately the conquest of Wu by Jin in 280.

The Three Kingdoms period including the collapse of the Han was one of the most dangerous in Chinese history due to multiple plagues, widespread famines, and civil war. A nationwide census taken in 280, following the reunification of the Three Kingdoms under the Jin showed a total of 2,459,840 households and 16,163,863 individuals which was only a fraction of the 10,677,960 households, and 56,486,856 individuals reported during the Han era. While the census may not have been particularly accurate due to a multitude of factors of the times, in 280, the Jin did make an attempt to account for all individuals where they could.

Chinese star names (Chinese: 星名, xīng míng) are named according to ancient Chinese astronomy and astrology. The sky is divided into star mansions (星宿, xīng xiù, also translated as "lodges") and asterisms (星官, xīng guān). The ecliptic is divided into four sectors that are associated with the Four Symbols, guardians in Chinese mythology, and further into 28 mansions. Stars around the north celestial pole are grouped into three enclosures (垣, yuán). The system of 283 asterisms under the Three Enclosures and Twenty-Eight Mansions was established by Chen Zhuo of the Three Kingdoms period, who synthesized ancient constellations and the asterisms created by early astronomers Shi Shen, Gan De and Wuxian. Since the Han and Jin dynasties, stars have been given reference numbers within their asterisms in a system similar to the Bayer or Flamsteed designations, so that individual stars can be identified. For example, Deneb (α Cyg) is referred to as 天津四 (Tiān Jīn Sì, the Fourth Star of Celestial Ford).

In the Qing dynasty, Chinese knowledge of the sky was improved by the arrival of European star charts. Yixiang Kaocheng, compiled in mid-18th century by then deputy Minister of Rites Ignaz Kögler, expanded the star catalogue to more than 3000 stars. The newly added stars (增星, zēng xīng) were named as 增一 (zēng yī, 1st added star), 增二 (zēng èr, 2nd added star) etc. For example, γ Cephei is referred to as 少衛增八 (Shào Wèi Zēng Bā, 8th Added Star of Second Imperial Guard). Some stars may have been assigned more than one name due to the inaccuracies of traditional star charts.

Chinese Empire (traditional Chinese: 中華帝國; simplified Chinese: 中华帝国; pinyin: Zhōnghuá Dìguó), or Empire of China, refers to the realm ruled by the Emperor of China during the era of Imperial China. It was coined by western scholars to describe the Ming and Qing dynasties (or imperial Chinese dynasties in general). Another term was the "Celestial Empire", in reference to the status of the emperor as the Son of Heaven. In 221 BC, China was unified under an emperor for the first time, and various imperial dynasties ruled China for a total of two millennia since then, including the Qin, Han, Jin, Sui, Tang, Song, Yuan, Ming, and Qing, among others.

Buyeo (Korean: 부여; Korean pronunciation: [pu.jʌ]; Chinese: 夫餘/扶餘; pinyin: Fūyú/Fúyú), also rendered as Puyŏ or Fuyu, was an ancient kingdom that was centered in northern Manchuria in modern-day northeast China. It had ties to the Yemaek people, who are considered to be the ancestors of modern Koreans. Buyeo is considered a major predecessor of the Korean kingdoms of Goguryeo and Baekje.

According to the Book of the Later Han, Buyeo was initially placed under the jurisdiction of the Xuantu Commandery, one of Four Commanderies of Han in the later Western Han. Buyeo entered into formal diplomatic relations with the Eastern Han dynasty by the mid-1st century AD as an important ally of that empire to check the Xianbei and Goguryeo threats. Jurisdiction of Buyeo was then placed under the Liaodong Commandery of the Eastern Han. After an incapacitating Xianbei invasion in 285, Buyeo was restored with help from the Jin dynasty. This, however, marked the beginning of a period of decline. A second Xianbei invasion in 346 finally destroyed the state excepting remnants in its core region; these survived as vassals of Goguryeo until their final annexation in 494.

The Sixteen Kingdoms (simplified Chinese: 十六国; traditional Chinese: 十六國; pinyin: Shíliù Guó), less commonly the Sixteen States, was a chaotic period in Chinese history from AD 304 to 439 when northern China fragmented into a series of short-lived dynastic states. Most of these regimes were created by groups such as the Xiongnu, Xianbei, Di, Jie, and Qiang, who had moved into northern and western China over earlier centuries and rose in rebellion against the Western Jin dynasty in the early fourth century. Some states were founded by the Han as well. Regardless of their rulers' background, every state adopted dynastic institutions in the Han tradition and styled itself as a legitimate monarchy. These states often fought one another and also contended with the Eastern Jin dynasty, which governed the south after the collapse of Western Jin in 317. The era ended in 439, when Northern Wei, founded by the Tuoba clan of the Xianbei, reunified the north. The Eastern Jin dynasty had already collapsed in 420 and been replaced by the Liu Song dynasty, the first of the Southern Dynasties. After the consolidation of the north, Chinese history entered the period known as the Northern and Southern Dynasties.

The term "Sixteen Kingdoms" was first used by the 6th-century historian Cui Hong in the Spring and Autumn Annals of the Sixteen Kingdoms and refers to the five Liangs (Former, Later, Northern, Southern and Western), four Yans (Former, Later, Northern, and Southern), three Qins (Former, Later and Western), two Zhaos (Han/Former and Later), Cheng-Han and Xia. Cui Hong did not count several other kingdoms that appeared at the time including the Ran Wei, Zhai Wei, Chouchi, Duan Qi, Qiao Shu, Huan Chu, Tuyuhun and Western Yan. Nor did he include the Northern Wei and its predecessor Dai, because the Northern Wei is considered to be the first of the Northern Dynasties in the period that followed the Sixteen Kingdoms.

The Northern and Southern dynasties (Chinese: 南北朝; pinyin: Nán běi cháo) was a period of political division in the history of China that lasted from 420 to 589, following the tumultuous era of the Sixteen Kingdoms and the Eastern Jin dynasty. It is sometimes considered to be the latter part of a longer period known as the Six Dynasties (220–589). The period featured civil war and political chaos. However, it was also a time of flourishing arts and culture, advancement in technology, and the spread of Mahayana Buddhism and Taoism. The period saw large-scale migration of Han Chinese people to lands south of the Yangtze. It came to an end with the unification of China proper by Emperor Wen of the Sui dynasty in 589.

During this period, the process of sinicization accelerated among the non-Han ethnicities in the north and the indigenous peoples in the south. This process was also accompanied by the increasing popularity of Buddhism in both northern and southern China. Daoism gained influence as well, with two essential Daoist canons written during this period. Additionally, many notable technological advances occurred during this period. The invention of the stirrup during the earlier Jin dynasty (266–420) helped spur the development of heavy cavalry as a combat standard. Historians also note advances in medicine, astronomy, mathematics, and cartography. Intellectuals of the period include the mathematician and astronomer Zu Chongzhi (429–500), and astronomer Tao Hongjing (456–536).

Wei (Chinese: 魏), also known as Cao Wei (曹魏) or Former Wei, was one of the major dynastic states in China during the Three Kingdoms period. The state was established in 220 by Cao Pi based upon the foundations laid by his father Cao Cao during the end of the Han dynasty. Its capital was initially located at Xuchang, and was later moved to Luoyang.

The name Wei first became associated with Cao Cao when he was named the Duke of Wei by the Eastern Han government in 213, and became the name of the state when Cao Pi proclaimed himself emperor in 220. Historians often add the prefix "Cao" to distinguish it from other Chinese states known as Wei. The authority of the ruling Cao family dramatically weakened following the deposition and execution of Cao Shuang, a regent for the dynasty's third emperor Cao Fang. Beginning in 249, another regent in Sima Yi gradually consolidated state authority for himself and his relatives, with the last Wei emperors largely being puppets of the Sima family. In 266, Sima Yi's grandson Sima Yan forced Emperor Yuan to abdicate, proclaiming himself to be emperor of the newly established Jin dynasty; he would be posthumously known as Emperor Wu (of Jin).

The end of the (Eastern) Han dynasty was the period of Chinese history from 189 to 220 CE, roughly coinciding with the tumultuous reign of the Han dynasty's last ruler, Emperor Xian. It was followed by the Three Kingdoms era (220–280 CE). During the end of the Han dynasty, the country was thrown into turmoil by the Yellow Turban Rebellion (184–205). Meanwhile, the Han Empire's institutions were destroyed by the warlord Dong Zhuo and fractured into regional regimes ruled by various warlords, some of whom were nobles and officials of the Han imperial court. The warlord Cao Cao took control of Emperor Xian and his court in 196 and began gradually reunifying the empire. Cao Cao ostensibly operated under Emperor Xian's rule, though in reality the emperor was a hostage.

Cao Cao's efforts to reunify China were rebuffed at the Battle of Red Cliffs in 208–209, when his armies were defeated by the allied forces of Sun Quan and Liu Bei. The Han dynasty formally ended in 220 when Cao Cao's son and heir, Cao Pi, pressured Emperor Xian into abdicating in his favour. Cao Pi became the emperor of a new dynasty, Cao Wei. In response, Liu Bei established the Shu Han dynasty in 221 with himself as its emperor. Sun Quan founded the Eastern Wu dynasty in 222, first adopting the title of king and later declared himself emperor in 229. The period from the end of the Han dynasty in 220 to the reunification of China proper under the Western Jin dynasty in May 280 is known as the Three Kingdoms era in Chinese history.