[4] He was born in Jiangling and moved to Dunhuafang, Chang'an, Jingzhao in the early Sui Dynasty.
[3][6] The historian of education Shen Guanqun [zh] praised Yan for being "erudite and good at writing".
[7] On the topic of scripture meanings, Yan engaged Liu Zhen [zh] in a debate.
[3] In the Sui dynasty, he served as a secretary for the Department of Economics and was a scholar of the Eastern Palace.
[7] Yan was chosen to be an assistant during the reign of Emperor Taizong of Tang and later received a general title (Chinese: 踰岷將軍).