The Xianbei (; simplified Chinese: 鲜卑; traditional Chinese: 鮮卑; pinyin: Xiānbēi) were an ancient nomadic people who inhabited parts of present-day northeastern China, Inner Mongolia, and the eastern Eurasian steppe. The Xianbei were likely not of a single ethnicity, but rather a multilingual, multi-ethnic confederation consisting of mainly Proto-Mongols (who spoke either pre-Proto-Mongolic, or Para-Mongolic languages), and, to a minor degree, Tungusic and Turkic peoples. They originated from the Donghu people who splintered into the Wuhuan and Xianbei when they were defeated by the Xiongnu at the end of the 3rd century BC. In the 1st century BC, the Xianbei began engaging in the conflict between the Han dynasty and the Xiongnu, culminating in the Xianbei replacing the Xiongnu on the Mongolian Plateau.
The chieftain Tanshihuai unified the Xianbei in the mid-2nd century and waged war against the Han dynasty but the Xianbei splintered following his death in 181 AD. After suffering several defeats by the end of the Three Kingdoms period, the Xianbei migrated southwards and settled close to Han society and submitted to the Chinese dynasties. As one of the "Five Barbarians", they fought as auxiliaries for the Western Jin dynasty during the War of the Eight Princes and the Upheaval of the Five Barbarians before declaring independence while the Jin were pushed out from northern China. During the Sixteen Kingdoms period, the Xianbei founded several short-lived states and established themselves in the Central Plains.
The Xianbei were at one point all subjected to the Di-led Former Qin dynasty before it fell apart not long after its defeat in the Battle of Fei River. In the wake of the Qin collapse, the Tuoba founded the Northern Wei dynasty and reunited northern China, ushering China into the Northern and Southern dynasties period. The Northern dynasties, all of which were either led or heavily influenced by the Xianbei, opposed and promoted sinicization at one point or another but tended towards the latter, merging with the general Chinese population by the Tang dynasty. The Northern Wei Emperor Xiaowen in particular implemented policies that suppressed Xianbei customs while promoting Han culture at court such as language, dress, and rituals. He arranged for ethnic Han elites to marry daughters of the Tuoba imperial clan in the 480s AD. More than fifty percent of Tuoba Xianbei princesses of the Northern Wei were married to southern Han men from the imperial families and aristocrats from southern China of the Southern dynasties who defected and moved north to join the Northern Wei.
Paul Pelliot tentatively reconstructs the Eastern Han Chinese pronunciation of Xianbei (鮮卑) as */serbi/, from *Särpi, after noting that Chinese scribes used 鮮 to transcribe Middle Persian sēr (lion) and 卑 to transcribe foreign syllable /pi/; for instance, Sanskrit गोपी gopī "milkmaid, cowherdess" became Middle Chinese 瞿卑 (ɡɨo-piᴇ) (> Mand. qúbēi).
On the one hand, *Särpi may be linked to the Mongolic root *ser ~*sir which means "crest, bristle, sticking out, projecting, etc." (cf. Khalkha сэрвэн serven), possibly referring to the Xianbei's horses (semantically analogous with the Turkic ethnonym Yabaqu < Yapağu 'matted hair or wool', later 'a matted-haired animal, i.e. a colt'). On the other hand, the Book of the Later Han and the Book of Wei stated that before becoming an ethnonym, Xianbei had been a toponym, referring to the Great Xianbei mountains (大鮮卑山), which is now identified as the Greater Khingan range (simplified Chinese: 大兴安岭; traditional Chinese: 大興安嶺; pinyin: Dà Xīng'ān Lǐng).
Schuessler (2014) reconstructs 鮮卑's Old Chinese pronunciation in the 1st century BCE as *sen-pe, and Eastern Han Chinese pronunciation as sian pie; while reconstructing no syllable coda -r for 鮮's pronunciation in any of those two stages, Schuessler remarks that "[i]n syllable-final position n represents foreign n as well as r and perhaps l", and still derives both *sian pie and *sen-pe from foreign *Särbi.
Shimunek (2018) reconstructs *serbi for Xiānbēi and *širwi for 室韋 Shìwéi < MC *ɕiɪt̚-ɦʉi.
Warring States period's Chinese literature contains early mentions of Xianbei, as in the poem The Great Summons in the anthology Chu Ci and possibly the chapter "Discourses of Jin 8" in the Guoyu. However the early appearance of the word xianbei in the Chu ci refers to a belt buckle rather than a people.
The first time the Xianbei people appeared in recorded history was in the Book of the Later Han, compiled in the 5th century. According to the Book of the Later Han, the Xianbei were originally a branch of the Donghu people together with the Wuhuan (or Wuwan) and "the language and culture of the Xianbei are the same as the Wuhuan". When the Donghu "Eastern Barbarians" were defeated by the Xiongnu leader Modu Chanyu around 208 BC, the Donghu splintered into the Xianbei and Wuhuan. The Xianbei were driven into the Khingan Mountains in northeastern Inner Mongolia. The Xianbei practiced some agriculture, or at least more than the Xiongnu. They wielded bows made of horn and produced fur garments made of sable and other pelts. Archaeological remains of a Han dynasty Xianbei site in northeastern Inner Mongolia include skeletons of roebuck, deer, wild pigs, and hunting tools.
Since the Xianbei are described as identical to the Wuhuan in culture and language, it can be assumed that descriptions of the Wuhuan apply to the Xianbei as well. According to a description of the Wuhuan by a Chinese historian who died in 266, they were nomads who moved to find new land for herds to graze, although they also practiced some agriculture. They took the personal names of their strongmen as their surnames. Family life was matriarchal except when it came to warfare. However these might just be stereotypes to reinforce a non-Chinese "other" by the authors.
The first significant contact the Xianbei had with the Han dynasty was in 41 and 45, when they joined the Wuhuan and Xiongnu in raiding Han territory.
In 49, the governor Ji Tong convinced the Xianbei chieftain Pianhe to turn on the Xiongnu with rewards for each Xiongnu head they collected.
In 54, Yuchouben and Mantou of the Xianbei paid tribute to Emperor Guangwu of Han.
In 58, the Xianbei chieftain Pianhe attacked and killed Xinzhiben, a Wuhuan leader causing trouble in Yuyang Commandery.
In 85, the Xianbei secured an alliance with the Dingling and Southern Xiongnu.
In 87, the Xianbei attacked the Xiongnu chanyu Youliu and killed him. They flayed him and his followers and took the skins back as trophies.
In 91, the Northern Xiongnu were defeated by the Han dynasty and the Xianbei began occupying the Mongolian Plateau, absorbing 100,000 Xiongnu tribes and increasing their strength.
In 109, the Wuhuan and Xianbei attacked Wuyuan Commandery and defeated the local Han forces. The Southern Xiongnu chanyu Wanshishizhudi rebelled against the Han and attacked the Emissary Geng Chong but failed to oust him. Han forces under Geng Kui retaliated and defeated a force of 3,000 Xiongnu but could not take the Southern Xiongnu capital due to disease among the horses of their Xianbei allies.