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 318, after suppressing a coup by a powerful minister in the Xiongnu-Han court, in which the emperor and a large proportion of the aristocracy were massacred), the Xiongnu prince Liu Yao moved the Xiongnu-Han capital from Pingyang to Chang'an and renamed the dynasty as Zhao (Liu Yuan had declared the empire's name Han to create a linkage with Han Dynasty—to which he claimed he was a descendant, through a princess, but Liu Yao felt that it was time to end the linkage with Han and explicitly restore the linkage to the great Xiongnu chanyu Maodun, and therefore decided to change the name of the state. (However, this was not a break from Liu Yuan, as he continued to honor Liu Yuan and Liu Cong posthumously; it is hence known to historians collectively as Han Zhao).