佛祖統紀 40.61

40.61

In the first month, Lord Lao descended outside the Danfeng Gate, standing atop a cloud, and said to the Adjutant Tian Tongxiu: 'When I entered the shifting sands, I hid a golden casket with numinous talismans in the former residence of Magistrate Yin in Taolin. You may report this so that it can be retrieved to protect the realm.' Tongxiu reported this. An imperial order commanded him to go and seek it. They saw purple clouds and a white hare beneath Yin's Terrace; digging there, they obtained a golden casket with jade tablets inscribed in vermilion with delicate seal script. It was welcomed and placed in Lingchang Hall. That night, throughout the towers and open sky, there were divine lamps. The hundred officials submitted a memorial noting that the talismanic omens had covertly corresponded, and an imperial decree was issued changing the era name to Tianbao.
In the second month, imperial decrees conferred the titles: Zhuangzi as True Person of Nanhua; Wenzi as True Person of Tongxuan; Liezi as True Person of Chongxu; and Gengsangzi as True Person of Dongling. The books of the four masters were designated as True Scriptures (Zhenjing), and one professor and one assistant instructor each were established, along with one hundred students.