 Chen sent Wang Huang to Modu, the "chanyu" of the Xiongnu to his north, to seek help from the nomads.For his part, the king of Yan sent Zhang Sheng (t s "Zhāng Shèng") to convince the Xiongnu that Chen's rebellion stood no chance of success and that they should refrain from involving themselves.En route, however, Zhang met Zang Yan ( "Zāng Yǎn") whose father Zang Tu had been the previous king of Yan before his execution by the Han emperor.