《北史·列传·卷四》
孝昌元年，法僧杀死了行台高谅，在彭城反叛，自称帝号，改年号为天启。
孝昌元年，法僧杀行台高谅，反于彭城。自称尊号，改元天启。
In the first year of Xiaochang, Fa Seng killed Xingtai Gaoliang and rebelled in Pengcheng, claiming himself to be an emperor, and changed the name of the reign to Tianqi.