Centrally located in the pre-Islamic city of Zavarah, this mosque is the earliest dated example of a four-iwan plan scheme. Contrary to most Seljuk mosques, the inscription containing the date and the patronage for the building is located on the courtyard façade. Although this information is not completely preserved, a date of 1135 (530 A.H.) can be established for this building. The patron of the mosque is identified as Abu Tahir Husayn ibn Ghali ibn Ahmad. In another inscription on the eastern side of the south iwan, the date of the mihrab is recorded as 1156 (551 A.H.).

The mosque has a rectangular plan that is nine bays long and seven deep. In the center is a courtyard that is surrounded on all sides by arcades. A minaret is located on the northwest side of the mosque and is accessed through a narrow passageway that opens two bays in from the north wall. Of the three entries into the mosque, an entrance located on the north end of the east side of the building is the main public access. The other two entries are located at two ends of the west side of the building.

Four iwans mark the centers of the courtyard facades. The north and south iwans are taller, marking the importance of the north-south axis along which the entry to the mosque chamber and the mihrab are located. The arcades consist of a series of pointed barrel vaults oriented perpendicular to the main north-south axis of the building. The three bays adjacent to the dome chamber and the south iwan are the widest. A series of octagonal and rectangular piers support the vaults. 

The dome chamber, located on the south side of the mosque, is square in plan; above its walls is an octagonal zone of transition between the square plan and the dome. Located on the east and west sides of the chamber are two tall arched openings that give access to the flanking bays. Above the arches, a band of Kufic inscriptions with a vegetal background wraps the interior. Although this inscription is damaged, its contents can be identified as parts of the sura al-'Imran. This inscription originally also included the date of the monument, but this part has not survived. Above the inscription, four three lobed squinches, similar to the squiches in the Friday mosque of Isfahan, bridge the corners of the square plan. Above these squinches are sixteen pointed arch niches crowned by the dome. The interior surface of the dome is decorated with different colored bricks in cross-patterns and ribs which originate at the dome's apex.

The mihrab, located on axis with the main entrance, is the most decorated feature of the interior. It consists of two rectangular epigraphic frames containing two orders of pointed arch niches that are supported on slender pairs of engaged columns. It contains three inscriptions; the inscription on the outermost frame is in Kufic with a vegetal background, and contains verses from the al-'Asr (time) sura. The inner rectangular inscription is in Thuluth script, and contains verses from the Tauba (repentance) sura. The inscription framing the pointed arch of the mihrab, also in Thuluth, is another verse from the Al 'Imran (the family of Imran) sura. The spandrels and the tympanum of the arch of the mihrab are decorated with floral and sinuous decorations. 

Hatim, Ghulam 'Ali. Mimari-i Islami-i Iran dar dawrah-i Saljuqiyan. Tehran: Muassasah-i Intisharat-i Jihad-i Danishgahi, 2000.

Pope, Arthur U. and Phyllis Ackerman (ed). A Survey of Persian Art from Prehistoric Times to the Present, Vol. 3. London, New York: Oxford University Press, 1964.