Xiongnu
The Xiongnu () were a confederation of nomadic peoples who, according to ancient Chinese sources, inhabited the eastern Asian Steppe from the 3rd century BC to the late 1st century AD. Chinese sources report that Modu Chanyu, the supreme leader after 209 BC, founded the Xiongnu Empire.
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.