The Fayuansi, one of the oldest Buddhist temples in Beijing, is situated in the Xuanwumen area in the southwest quarter of the city. According to the Shuntian Prefecture Annals, Li Shimin, the second emperor officers and soldiers who lost their lives in battles, built the temple in 645.

At the time it was called the Minzhongsi (the Temple in Memory of the Loyal). It was rebuilt in the Zhengtong period (1436-1449) of the Ming Dynasty and renamed the Temple of Exalted Happiness (Chongfusi). Its present name dates from 1734.

[source:ebeijing.gov.cn]