Golpayegan Friday Mosque dates back to Seljuk period. Sultan Muhammad Tapar I ordered it to be constructed between 1105 and 1118 AD. The dome chamber is the only structure which remains standing now from the original construction. The Qajar rulers reconstructed the building and included four eyvans in it.
The style of architecture is reminiscent of the Sassanian temple structure according to one hypothesis. The dome was made into a chahar taq (a square domed structure having four arched entrances in the middle of each side) with a minaret at the side. There was a huge courtyard surrounded by walls and people gathered here to offer their prayers.
The architecture of this temple has changed somewhat over time. There used to be wooden columns supporting a hypostyle hall with a roof. The dome chamber was there in the center of it. What you can see today when you visit this mosque in Iran is the remaining parts rebuilt from Qajars period, nineteenth century.
It is rectangular in shape with vaulted ceilings, domed prayer halls and a rectangular courtyard. There are four eyvans on every side of the courtyard. You can enter through the huge northeast iwan. There is a sanctuary beyond the southwest eyvan and there is a Seljuk dome chamber here with a mihrab on the qibla wall.
The sanctuary in Golpayegan Friday Mosque is made of brick with vaulted archways. You can see muqarnas squinches which follow to the shallow brick dome. There are honeycomb windows in the base of the dome which let in the sunlight from outside. Kufic inscriptions can be seen around these windows.
The mihrab on the qibla wall inside the dome chamber is topped by a stucco muqarnas hood. There are inscriptions on the blind arch above along with a plaque. Kufic inscriptions with geometric motifs surround the mihrab too.
There are brick panels in the interiors, again with Kufic inscriptions and geometric motifs. Tiles were used to decorate the area. There is nothing on the exterior except a ring of large diamonds on the base of the dome. Another structure remaining from the Seljuk period is the minaret which can be found behind the qibla wall. The shaft is decorated with brick patterns while the top has turquoise tiles. Tourists flock to see this beautiful Golpayegan Friday Mosque when they visit Iran.