Molla Esma'il Mosque

Situated adjacent to the center of the town of Yazd, the complex of the Friday mosque of Yazd was founded in the twelfth century; however, what stands on the site today is the new mosque (masjid-i jadid) built in 1324 under the Il Khanids, and later augmented in 1365 under the Muzaffarids. During the eighteenth and nineteenth centuries the mosque underwent further developments that added to its medieval nucleus. These multiple historical layers are most evident in the courtyard: to the east are the ruins of an early, pre-Saljuk mosque; to the south are fourteenth-century structures, and to the west are late eighteenth and nineteenth-century additions.
According to Tarikh-i-jedid-i-Yazd ("The New History of Yazd"), written in 1323 CE by Ahmad ibn Husayn ibn 'Ali al-Kateb, the site adjacent to the earlier mosque was acquired by Sayyed Rukn ad-din Muhammad, who ordered the construction of an iwan with upper galleries, a domed chamber, and halls for prayer. Despite his death in 1330, work continued until the iwan and its galleries were completed. Three important aspects distinguish the Friday mosque of Yazd: its structural innovation, its remarkable decoration, and its being the "earliest" mosque upon which later fifteenth-century mosques in the Yazd region were modeled.

The mosque encloses a rectangular open court, measuring approximately 18 by 46 meters. (Sources differ on these measurements; those described here are based upon a measured drawing). The court surrounded on all four sides by one-story arcades of pointed-arch vaults resting on massive square piers. The complex's main portal iwan is located on the east side of the court; the domed chamber (12 by 12 meters) with the main iwan preceding it occupies the center of the southern side of the court. The iwan has galleries on the second level. These permit access to the arcades' roofs, enabling circumnavigation of the complex. Two rectangular "winter" prayer halls flank the domed chamber and extend halfway along the western and eastern arcades' walls. The area of the building which includes the domed chamber and the two winter halls measures 46 by 54 meters; the courtyard including the bays of arcades measures 27 by 54 meters.