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.
Emperor Ming of Han
As crown prince, Crown Prince Zhuang was often requested by Emperor Guangwu to render opinions in important matters. In 51, he was involved in making a major correct decision in Han's relationship with Xiongnu. By that point, Xiongnu had a civil war and divided into two—with North Xiongnu ruled by Chanyu Punu (蒲奴) and South Xiongnu ruled by Chanyu Bi (比). Han had become allied with South Xiongnu, and in response, Chanyu Punu, also wanting peace with Han, requested a "heqin" marriage. Prince Zhuang suggested that Emperor Guangwu refuse the proposal, reasoning that North Xiongnu had only made the proposal to alienate South Xiongnu from Han. Emperor Guangwu agreed.