Originally constructed in 996 during the Northern Song Dynasty, the Ox Street Mosque is the biggest and oldest mosque in Beijing. When the mosque was first built by Nasruddin, the son of an Arabic priest who came to China to preach the Islamic faith, it was in pure Arabic style and used for astronomical observations needed for drawing up the Islamic calendar.
In 1442 during the Ming Dynasty, and in 1696 during the Qing Dynasty, the Mosque was repaired several times. Major renovation projects were carried out in 1442, during the time of Emperor Kangxi (1662-1722) and again after the founding of the People's Republic of China in 1949 when the buildings were entirely repainted and redecorated. During its many phases of reconstruction and renovation, however, elements of Chinese traditional architecture were adopted. Today, in terms of its structure and general layout, Islamic features still prevail.
Directly inside the front gate stands a hexagonal structure known as the Moon-Watching tower. Every year at the beginning and end of the fast serve the moon's waxing and waning so as to auspiciously fix the exact duration of the fast. In front of the tower are a memorial archway and a screen wall covered with carved murals, which together form the main entrance of the mosque.
The prayer hall, with its courtyard to the east, consists of five major areas. The three central areas, running lengthwise, are divided into five bays, some narrow with coffered ceilings, and some wide with high-beam ceilings. The two side wings have plain ceilings with beams laid lengthwise. At the entrance of the hall, the ceiling bears the Arabic names of noted imams around the world. Farther in, Chinese flower and cloud paintings mingle with Arabic inscriptions and patterns on the coffered ceilings, and the chandeliers are slightly reminiscent of Venetian glass. There is an arch between each pair of pillars, gleaming with gold patterns.
To the rear of the main hall is a group of small religious halls and stele pavilions designed in Islamic style. As the teaching of the Koran forbid the portrayal of human or animal forms, the designs and patterns in all of the decorations are composed of Arabic letters and geometrical patterns. Directly in the center of this section is the minaret, from which the muezzin calls the faithful for prayers five times a day, beginning at dawn.
The minaret (calling tower), a two-storey obelisk in the centre of the courtyard, was originally built as a script depository. Later imams used it as a calling tower. When prayer time came, they ascended the tower and recited the Koran, and Muslims living in the vicinity came to listen. On the ground floor is a large copper cauldron, which was used to prepare communal meals.
To the southeast of the tower lie the tombs of two Muslims who came from the Middle East and preached in the Mosque. The tomb for Ahmad Burdani was built in 1320, and the one for Ali in 1283. Both came from ancient Persia. The tombstones bear Arabic inscriptions and have been set into a nearby wall.
In the imam's library, there are Koran manuscripts and old wooden printing blocks. The mosque used to be a printing house as well.
At the south of the courtyard are the men's and women's prayer-preparation bathrooms. There are long-beaked kettles for the devout to use to wash their nostrils, ears, and mouths. It is considered sacrilegious to enter the mosque without cleaning oneself. Muslims must wash their whole bodies on Friday, the major prayer day. They only need to wash their heads, hands and feet on other days.