Chizhishizhuhou Chanyu
The southern Xiongnu were a branch of the eastern Xiongnu that followed the rebellious pretender Huhanye and in 51-53 BC moved en masse within the Han borders under protection of Chinese. Since the times of Huhanye, the status of the southern Xiongnu was loyal allies of the Han Dynasty. The southern Xiongnu enjoyed material support of the old "heqin" treaty, and in return guarded the Chinese northern borders and participated in the Chinese external and internecine conflicts as long as the Chinese court respected their independence. However, when the Han imperial court attempted to appoint an ineligible for the crown Western Jükü-Prince Yufuluo from ineligible Right Wing as a Chanyu, instead of respecting the traditional election, the southern Xiongnu dissented and elected a lawful alternate Hyuibu Gudu-heu. Later they expelled Yufuluo, who had to seek safety in exile at the Han imperial court.
Xiongnu
In 53 BC Huhanye (呼韓邪) decided to enter into tributary relations with Han China. The original terms insisted on by the Han court were that, first, the "chanyu" or his representatives should come to the capital to pay homage; secondly, the "chanyu" should send a hostage prince; and thirdly, the "chanyu" should present tribute to the Han emperor. The political status of the Xiongnu in the Chinese world order was reduced from that of a "brotherly state" to that of an "outer vassal" (外臣). During this period, however, the Xiongnu maintained political sovereignty and full territorial integrity. The Great Wall of China continued to serve as the line of demarcation between Han and Xiongnu.