He Yan
He Yan was, along with Wang Bi, one of the founders of the Daoist school of Xuanxue. He synthesised the philosophical schools of Daoism and Confucianism, believing that the two schools complemented each other. He wrote a famous commentary on the "Daode Jing" that was influential in his time, but no copies have survived. His commentary on the "Analects" was considered standard and authoritative for nearly 1000 years, until his interpretation was displaced by the commentary of Zhu Xi in the 14th century.