The Dongsi mosque is the oldest mosque in Beijing City. It is located at No.13, the Dongsi South Street, Dongcheng District. There are different sayings about the construction time of the mospue. Some people say that it was built in 1356 during the Yuan Dynasty (1271-1368), but some other people think it was constructed in the 12th
year (1447) during the Zhengtong reign of the Ming Dynasty (1368-1644) by a military officer named Chen You.
The mosque faces the east. The existing buildings include two gates, a minaret, a worship hall and so on. The first gate was rebuilt in 1920. Originally, there was a minaret inside the second gate. The worship hall can accommodate 500 people and the lections of the Alcoran are carved on the hall's arches. There are 5 wing halls and 3 wing rooms respectively on the southern and northern parts of the courtyard with ambulatories in front of all of them. These buildings feature the Ming Dynasty architectural style. Many precious cultural relics are preserved in the mosque. In the library located at the southern wing hall, you can find various versions of the Alcoran. The most precious one is a hand-written copy from the Yuan Dynasty. Also there are books presented by the emperor of Egypt.
The mosque is the headquarters of the Islamic Association of Beijing.