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.
Xunyu
Chinese annals contain a number of references to the "Xunyu". The earliest authors were Sima Qian (c. 145 or 135 BC – 86 BC), Ying Shao (AD 140-206), Wei Zhao (204-273), and Jin Zhuo (c. late 3rd or 4th century). Without citing any arguments, they claimed that "Xunyu" or "Xianyun" were names that designated nomadic people who during the Han dynasty were called "Xiongnu" (匈奴). That view was also held by the Tang dynasty commentator Sima Zhen (c. 8th century).