《汉书·传·匈奴传上》
单于很长时间没有能够与自己的大队人马相遇，右谷蠡王以为单于死了，便自立为单于。
单于久不与其大众相得，右谷蠡王以为单于死，乃自立为单于。
The Chanyu spent a long time before he was able to rejoin his main force, and King Youguli believed that he was dead. King Youguli therefore declared himself Chanyu.