Noin-Ula burial site
Many immigrants lived in the Xiongnu pasturelands, but at first they did not mix with the Xiongnu. To be a Xiongnu, one had to be a member of a clan, born of Xiongnu parents. The newcomers were well off, but were outsiders, and could marry only among themselves, not the Xiongnu. Only later did they intermix, increase in numbers, even created a state that existed from 318 to 350 AD.
History of Mongolia
In 48 AD, the Xiongnu empire was weakened as it was divided into the southern and northern Xiongnu. The northern Xiongnu migrated to the west. They established Üeban state (160–490) in modern Kazakhstan and Hunnic Empire (370s–469) in Europe. The Xianbei that were under the Xiongnu rebelled in 93 AD, ending the Xiongnu domination in Mongolia.