During the reign of Emperor Wu of Jin Dynasty, Cui Hong, the official minister, recommended him as the left prime minister. Later, when he became the secretariat of Yongzhou, Emperor Wu of Jin asked him what he thought of himself. He said, "I am like Guizhi in the Moon Palace and Baoyu on Kunlun Mountain." A laurel in Guanghan Palace and a Pian Yu in Kunlun Mountain are used to describe particularly outstanding talents, which is the origin of "the laurel of the moon". The moon is the moon palace, the palace of the moon. Emperor Wu of song laughed and praised him. After the Tang Dynasty, the imperial examination system prevailed, and the laurel of the moon was used as a metaphor for scholars who passed the examination.