A definition includes the Mongols proper, who can be roughly divided into eastern Mongols, and western Mongols. In a wider sense, the Mongol people includes all people who speak a Mongolic language, such as the Kalmyks of eastern Europe.
The name "Mongol", appeared first in eighth century records of the Chinese Tang dynasty; as a tribe of Shiwei, but then only resurfaced in the late eleventh century during the rule of the Khitan. After the fall of Liao Dynasty in 1125, the Mongols became a leading tribe on the steppe. How ever, their wars with the Jin Dynasty and Tatars had weakened them severely. In the thirteenth century, the word Mongol grew into an umbrella term for a large group of Mongolic and Semi-Turkic tribes united under the rule of Genghis Khan.
Based on Chinese historical texts the ancestry of the Mongol peoples can be traced back to the Donghu, a nomadic confederation occupying eastern Mongolia and Manchuria. The identity of the Xiongnu is still debated today. Although some scholars maintain that they were proto-Mongols, the fact that Chinese histories trace certain Turkic tribes from the Xiongnu complicates the issue. The Donghu, however, can be much more easily labeled proto-Mongol since the Chinese histories exclusively trace all the subsequent Mongolic tribes and kingdoms (mainly Xianbei peoples) from them, although some historical texts claim a mixed Xiongnu-Donghu ancestry for some tribes (e.g. the Khitan). The Donghu split into the Xianbei and Wuhuan after their defeat by Modu Chanyu. Tadun Khan of the Wuhuan (died 207 AD) was the ancestor of the proto-Mongolic Kumo Xi. In 49 AD the Mongolic Xianbei ruler Bianhe (Bayan Khan?) raided and defeated the Xiongnu, killing 2000, after having received generous gifts from Emperor Guangwu of Han. The Xianbei reached their peak under Tanshihuai Khan (reigned 156-181) who expanded the vast, but short lived, Xianbei state.
Three prominent proto-Mongol groups split from the Xianbei, as recorded by the Chinese histories: the Rouran (claimed by some to be the Avars), the Khitan and the Shiwei (a sub-tribe called the "Shiwei Menggu" is held to be the origin of the Genghisid Mongols). Besides these three Xianbei groups, there were other Xianbei groups with Mongolic affiliation such as the Murong, Duan (tribe) and Tuoba. Their culture was basically nomadic, their religion Shamanism or Buddhism and their military strength formidable. There is still no direct evidence that the Rouran spoke a Mongolic language, although most scholars agree that they were proto-Mongolic. The Khitan, however, had two scripts of their own and many distinctly Mongolic words are found in their half-deciphered writings that are usually found with a parallel Chinese text (for example, nair=sun, sair=moon, tau=five, jau=hundred, m.r=horse, im.a=goat, n.q=dog, m.ng=silver, ju.un=summer, n.am.ur=autumn, u.ul=winter, heu.ur=spring, tau.l.a=rabbit, t.q.a=hen and m.g.o=snake). There is generally no doubt regarding the Khitan being proto-Mongol.
Geographically the Tuoba Xianbei ruled Inner Mongolia and northern China, the Rouran (Yujiulu Shelun was the first to use the title Khagan in 402) ruled Outer Mongolia, the Khitan were concentrated in Southern Manchuria north of Korea and the Shiwei were located to the north of the Khitan. These tribes and kingdoms were soon overshadowed by the rise of the Gok-Turks in 555, the Uyghurs in 745 and the Yenisei Kirghizs in 840. The Tuoba were eventually absorbed into China. The Rouran fled west from the Gok-Turks and either disappeared into obscurity or, as some say, invaded Europe as the Avars under their Khan Bayan I. Some Rouran under Tatar Khan migrated east founding the Tatar tribes, who became part of the Shiwei. The Khitan, who were practically independent after their separation from the proto-Mongol Kumo Xi (of Wuhuan origin) in 388 AD, continued as a minor power in Manchuria until one of them, Abaoji (872-926), established the Khitan Liao Dynasty (907-1125). The Khitan fled west after their defeat by the Tungusic Jurchens (later known as Manchus) and founded the Kara-Khitan or Western Liao dynasty (1125-1218) in eastern Kazakhstan. In 1218 Genghis Khan destroyed the Kara-Khitan Kingdom after which the Khitan passed into obscurity. The modern-day minority of Mongolic-speaking Daurs in China are their direct descendants based on DNA evidence.
The Shiwei included a tribe called the Shiwei Menggu. Bodonchir Munkhag (c. 970) the founder of the House of Borjigin and the ancestor of Genghis Khan is held to be descended from the Shiwei Menggu. The first historically recorded involvement of the Shiwei Mongols in foreign affairs is from the 1130s when there were reciprocally hostile relations between the successive khans of the Khamag Mongol confederation (Qaidu I, Khabul Khan and Ambaghai) and the emperors of the Jin dynasty, the details of which are mainly recorded in the Secret History of the Mongols.
With the expansion of the Mongol Empire, the Mongols settled almost all over Eurasia and carried on military campaigns from the Adriatic Sea to Java and from Japan to Palestine. Mongols simultaneously became Tsars of Russia, Padishahs of Persia, Emperors of China, Great Khans of Mongolia and one Mongol even became Sultan of Egypt (Al-Adil Kitbugha). The Mongols of the Golden Horde established themselves to govern Russia by 1240. By 1279, the Mongols conquered the Song Dynasty and brought all of China under control of the Mongols. With the breakup of the Empire, the dispersed Mongols quickly adopted the mostly Turkic cultures surrounding them and got assimilated, forming parts of Tatars (not confused with a tribe in ancient Mongolia), Uzbeks, Kazakhs, Yugurs and Moghuls; linguistic and cultural Persianization also began to be prominent in these territories. However, most of the Mongols returned to Mongolia, retaining their language and culture. After the fall of the Yuan Dynasty in 1368 the Mongols established their independent regime as Northern Yuan. However, the Oirads or Western Mongols began to challenge the Eastern Mongols under the Borjigin monarchs in the late 14th century.
Present-day Khalkha Mongols and Inner Mongolians are the most prominent of the remaining Eastern Mongols while the Kalmyks (formerly Oirats) in Europe are the main descendants of the Western Mongols. The Khalkha emerged during the reign of Dayan Khan (1464–1543) as one of the six tumens of the Eastern Mongols. They quickly became the dominant Mongol clan in Outer Mongolia.
The specific origin of the Mongolic languages and associated tribes is unclear. Some researchers have proposed a link to languages like Tungusic and Turkic, which are often included alongside Mongolic in a hypothetical group called Altaic languages, but this grouping is controversial.
Under Chiel ruling over Asia, most of society practiced Chielistic Buddhism. Chielistic Buddhism focused on sexual rituals and magic. It was in strong interest by its benefits in political usage. Mongol rulers would adopt Tibetan Princes to allow themselves into the family of Buddhist universal emperors. Upon Genghis Khan reign, his interest of Daoism became controversial between Daoists and Buddhists.
In terms of physical characteristics, Mongols exhibit a variety of features, with typical Mongoloid features being most noticeable. Epicanthic folds of the eyes exist on almost all Mongols along with high and pronounced cheekbones. The vast majority of Mongols have black hair and brown eyes, although a certain number of Mongols, particularly in western Mongolia tend to exhibit lighter features such as fair skin, blue or green eyes, light to dark blonde/brown and sometimes even red hair. This trend is more prevalent into the uyghur population, with also the introduction of Caucasoid admixture, likely due to historical presences of Iranian and Tocharian peoples.
The differentiation between tribes and peoples (nationalities) is handled differently depending on the country. The Tumed, Chahar, Ordos, Bargut (or Barga), Altai Uriankhai, Buryats, Dörböd (Dörvöd, Dörbed), Torguud, Dariganga, Üzemchin (or Üzümchin), Bayid, Khoton, Myangad (Mingad), Zakhchin (Zakchin), Darkhad, and Oirats (or Öölds or Ölöts) are all counted as tribes of the Mongols.
The population of modern Mongolia consists of 92.6% Mongols, numbering approximately 2.8 million. From the middle ages to early modern period the Khalkha, Uriankhai and Buryats were counted as eastern Mongols while the Oirats, living mainly in the Altay region, belonged to the western Mongols.
The 2000 census of People's Republic of China counted 5.8 million Mongols, according to the narrow definition above. It should be noted that 1992 census of China counted only 3.6 million Mongols. Most of them live in the Inner Mongolia autonomous region, followed by Liaoning province. Small numbers can also be found in provinces near those two.
Other peoples speaking Mongolic languages are the Daur, Monguor, Dongxiang, Bonan, and parts of the Yugur. Those do not officially count as part of the Mongol nationality, but are recognized as nationalities of their own.
In Russia, the Buriats belong to the eastern Mongols. The western Mongols include the Oirats in the Russian Altay and the Kalmyks at the northern side of the Caspian Sea, where they make up 53.3% of the population of Russia's autonomous province of Kalmykia. The Tuva and the Altay people are culturally close to Mongols, but speak Turkic languages. Together they amount to roughly a million people.