《汉书·传·王莽传中》
当匈奴使者回去，单于知道来中原侍奉皇帝的儿子登前些时候已被处死，便出兵侵犯边境，王莽又调集军队去驻守。
会匈奴使还，单于知侍子登前诛死，发兵寇边，莽复发军屯。
When the Hun envoy returned, the Chanyu learned that his son who had come to the Central Plains to serve the emperor had been executed some time ago, so he sent troops to invade the border, and Wang Mang sent troops to guard it again.