Although today it is only partially extant, the Ali Shah Mosque is believed to have been the largest brick structure ever built. It was built in the Il-Khanid period by Ali Shah, the Iranian vizier during the reign of Oljeitu and Abu Sa'id. Ali Shah was not only its patron, but may also have been the designer of its plan.

The Ali Shah Mosque can be considered a courtyard mosque and is believed to have had a traditional layout, organized around four iwans. Uniquely, rather than having an additional domed structure to serve as the mosque building, the mihrab is housed in a proportionately majestic iwan, removing the need for a separate mosque structure.

Oriented towards qibla, the Ali Shah Mosque was organized around a marble paved rectangular courtyard that was 286 meters wide by 229 meters long. Entered through the pishtaq centered on the northern wall, it had an iwan at the centre of the west and east sides and the large iwan at the centre of the southernmost wall, towards the qibla. The mihrab, visible at the centre of the only extant qibla wall, is articulated by three relieving arches above it. On either side of the mihrab are two windows with sills located very high above ground level.

At the centre of the courtyard was a square pool with a square raised platform at its centre containing an octagonal fountain with jets and four lions sprouting water from their mouths in each direction. The walls of the courtyard were articulated with a stone-vaulted arcade of alabaster columns. Trees were organized in plots at each of the four corners surrounding the square pool.

In keeping with the grandiose scale of the few examples of Mongol architecture in Persia, the walls were massive brick structures. They were plain, articulated only by the curved corners of the qibla wall and the rounded bastion behind the mihrab recess which are partially still extant. The iwan vault was 30.5 meters wide and 48 meters deep with a total distance between the portal and the mihrab of 65.5 meters. The total height of the vault is said to have been over 45.7 meters and sprang from about 24 meters from the ground. Unfortunately, the vault of the huge iwan collapsed soon after it was built. Two minarets are also said to have risen from the same base of 24 meters up further 35.4 meters, for a total height above floor of approximately 61 meters. Attached to either side of the iwan walls were also a madrasa and a khanqa. These may have provided the funds necessary to sustain the mosque. Little is known about these two structures, as both have completely collapsed.

The Masjid-i-Jami of Ali Shah was later used as a citadel, perhaps because of its massive walls, and is thus locally known as the Arg (fortress). Most recently, the Arg has been used as an open air cinema.

Sources:

Hillenbrand, Robert. Islamic Architecture: Form, Function, and Meaning, 107, 424, 491. Edinburgh: Edinburgh University Press, 2000.

O'Kane, Bernard. Studies in Persian Art and Architecture, 125-126. Cairo: The American University of Cairo, 1995.

Pope, Arthur Upham. Persian Architecture: The Triumph of Form and Color, 177-179, 231. New York: George Braziller, Inc., 1965.

Wilber, Donald N. The Architecture of Islamic Iran: The Il Khanid Period, 146-149. New York: Greenwood Press, Publishers, 1955.