《后汉书·列传·西域传》
永建二年，班勇与敦煌太守张朗打败了他们，元孟这才派儿子到朝廷进贡。
永建二年，勇与敦煌太守张朗击破之，元孟乃遣子诣阙贡献。
In the second year of Yongjian, Ban Yong and Zhang Lang, the Prefect of Dunhuang, defeated them, and only then did Yuan Meng send his son to pay tribute to the court.