He Yan

He Yan (c. 195 – 9 February 249), courtesy name Pingshu, was a Chinese philosopher and politician of the state of Cao Wei in the Three Kingdoms period of China. He was a grandson of He Jin, a general and regent of the Eastern Han dynasty. His father, He Xian, died early, so his mother, Lady Yin, remarried the warlord Cao Cao. He Yan thus grew up as Cao Cao's stepson. He gained a reputation for intelligence and scholarship at an early age, but he was unpopular and criticised for being arrogant and dissolute. He was rejected for government positions by both emperors Cao Pi and Cao Rui, but became a minister during the rule of Cao Shuang. When the Sima family took control of the government in a coup d'état in 249, he was executed along with all the other officials loyal to Cao Shuang.

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.