  A second major commentary is the Laozi zhigui (The Essential Meaning of the Laozi) attributed to the Han dynasty scholar Yan Zun (fl. 83 B.C.E.–10 C.E.). Styled Junping, Yan’s surname was originally Zhuang; it was changed in later written records to the semantically similar Yan to comply with the legal restriction not to use the name Zhuang, which was the personal name of Emperor Ming (r. 57–75) of the Later or Eastern Han dynasty. Yan Zun is well remembered in traditional sources as a recluse of great learning and integrity, a diviner of legendary ability, and an author of exceptional talent. The famous Han poet and philosopher Yang Xiong (53 B.C.E.–18 C.E.) studied under Yan and spoke glowingly of him.