The Tribes of Mongolia: A Brief Introduction
The Tribes of Mongolia in the 12 century is a bit of a complicated topic, so here is an introduction into the most important of them around the time of Temujin's birth (1162)
You can see the rise of Chinggis Khan here: https://youtu.be/mYe5uYXb5PI
The Naiman: living in Western Mongolia/Kazakhstan area, around the Altai mountains. Turkic, Nestorian Christians, most powerful tribe on the steppe until the 1190s with the death of Inanch Khan, who would then split power between his sons Buiruk and Tayang.
The Kereid (numerous spelling variations of this name, so sound it out if you get stuck on it): South-central Mongolia bordering the Gobi desert. Turkic, Nestorian-Christians, not nearly as unified as the Naiman but still the second most important tribe in the 12th century. Ruled for almost the entire second half of the century by Toghrul Khan (the Ong Khan), who routinely lost his throne every few years.
The Tatars: In Eastern Mongolia near the Manchurian border, vassals of the Jin who ruled North Eastern China. Made up of numerous clans and subclans loosely connected. This name has little to do with Europeans calling the Mongols Tartars, but it is the reason the Chinese knew them as that.
The Merkit: Northern Mongolia, around Lake Baikal. 3 main, antagonistic clans. The chief of one, Toqto'a Beki, would kidnap Borte in the 1180s and kick off all of this trouble.
The Mongols: Originally just one tribe on the steppe, split into numerous clans, mainly the Taychiud (Targutai's clan) the Borjigin (Temujin's clan) and the Jadaran (Jamuhka's clan). Ruled in a confederation known as the Khamag Mongol in the first half of the 12th century, until machinations by the Jin and Tatars brought it to an end shortly before Temujin's birth. After the proclamation of the Mongol Empire in 1206 Mongol would come to refer to most of the steppe tribes, but clan distinctions would remain albeit in an altered form.