《明史·列传·卷五十七》
量泰二年，也先派遣使者入朝进贡，并且请求派遣回复的使者。
二年，也先遣使入贡，且请答使。
In the second year of Emperor Yingzong's reign, Yesian sent envoys to the Ming imperial court to present tribute and also to request the dispatch of envoys in reply.