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.
Xiongnu
An early reference to the Xiongnu was by the Han dynasty historian Sima Qian who wrote about the Xiongnu in the "Records of the Grand Historian" ( BC), drawing a distinct line between the settled Huaxia people (Chinese) to the pastoral nomads (Xiongnu), characterizing it as two polar groups in the sense of a civilization versus an uncivilized society: the Hua–Yi distinction. Pre-Han sources often classify the Xiongnu as a "Hu" people, which was a blanket term for nomadic people in general; it only became an ethnonym for the Xiongnu during the Han.