The Friday mosque of Semnan is one of the earliest mosques built in Iran; its minaret, the oldest part of the mosque, was built in the Seljuk period by Abu Harb Bakhtiar, an army commander. It carries an inscription indicating that it was built between 1026 CE (417 AH) and 1073 CE (466 AH). The mosque was later expanded during the Ilkhanid (1256-1353) and Timurid (1370-1506) periods.
The mosque is found inside the Semnan city bazaar, and its main entrance is on the north side from Emam street. Another entrance is found on the east side. Rectangular in plan, the mosque is oriented west-east and centers on a twenty-five by twenty-seven meter courtyard. Having developed over different dynasties, the mosque consists of a large qibla iwan on the west side and three vaulted praying halls on the other sides. The Seljuk minaret is located in the northeast corner.
The great iwan is made of brick and measures twenty-one meters high by ten and a half meters wide. Its inscription indicates that it was built in 1423 (827 AH) by a Timurid minister. Behind the iwan is a square area that is fourteen and a half meters high; this space is covered by a large dome. The mihrab is located on the western wall of the hall. Three other prayer halls enclose the courtyard. The south and north prayer halls both contain sixteen round, thick columns that support vaults above. The latter also features a remarkable carved door that leads to the main entrance. The east prayer hall leads to an octagonal space, the entry from the Hazrat bazaar; this hall also leads to the minaret, which is twenty-eight and a half meters high with a tall cylindrical base. This minaret was renovated in the Safavid period. Like other minarets of the Seljuk period, it was originally detached from the mosque.
The mosque is constructed of brick. Within the prayer halls, the columns are also brick, and the vaults are stuccoed. The great iwan is ornamented with elaborate brickwork, two polychrome inscriptions, and a tile band. Tilework is also found in the east entrance. The minaret, also built of brick, tapers sharply towards a muqarnas cornice formed of polychrome tiles. An octagonal balcony with a Safavid-style handrail is found at the top of the minaret. The minaret is further decorated with brick geometric designs and rough Kufic scripts.
Godard, André. The Art of Iran. New York: Frederick A. Praeger Publishers. 1965.