《元史·列传·卷三十四》
太祖十三年，蒙古军出紫荆口，张柔率所部迎战于狼牙岭，战败被俘，于是率众降蒙古，太祖仍令他官居原职。
戊寅，国兵出紫荆口，柔率所部逆战于狼牙岭，马蹶被执，遂以众降，太祖还其旧职，得以便宜行事。
In the 13th year of the Taizu reign, the Mongolian army emerged from Zijing Pass, and Zhang Rou led his troops to engage them in battle at Langyaguan, where he was defeated and taken prisoner. He then surrendered to the Mongols, but Taizu reinstated him in his original post.