Masjid-e-Jāmeh Isfahān (مسجد جامع اصفهان), also known as the Friday Mosque (مسجد جمعه) or the Masjid Jameh Atiq (مسجد جامع عتیق), is the grand, congregational mosque (Jāmeh) of Isfahān city, within Isfahān Province, Iran. The mosque is the result of continual construction, reconstruction, additions and renovations on the site from around 771 to the end of the 20th century.

This is one of the oldest mosques still standing in Iran, and it was built in the four-iwan architectural style, placing four gates face to face. The mosque’s core structure dates primarily from the 11th century when the Seljuk Turks established Isfahan as their capital. Ablution fountain can be seen in the foreground. Under the reign of Malik Shah I (ruled 1072-1092) and his immediate successors, the mosque grew to its current four-iwan design. The mosque has been a UNESCO World Heritage Site since 2012.

Built during the Umayyad dynasty, it is rumored in Isfahan that one of the pillars of this Mosque were personally built by the Caliph in Damascus. Prior to it becoming a Mosque, it is said to have been a house of worship for Zoroastrians. Responding to functional needs of the space, political ambition, religious developments, and changes in taste, over the centuries additions and modifications took place incorporating elements from the Mongols, Muzzafarids, Timurids and Safavids.

Of the most note is the elaborately carved stucco mihrab commissioned in 1310 by Mongol ruler Oljaytu, located in a side prayer hall built within the western arcade. This part of a building is named Oljaytu Mosque. The exquisite stucco mihrab is adorned with dense Quranic inscriptions and floral designs.

This domed interior was reserved for the use of the ruler and gives access to the main mihrab of the mosque.

The cupolas and piers that form the hypostyle area between the iwans are undated and varied in style, endlessly modified with repairs, reconstructions and additions. Dome soffits (undersides) are crafted in varied geometric designs (inspect) and often include an oculus, a circular opening to the sky. Vaults, sometimes ribbed, offer lighting and ventilation to an otherwise dark space.

The qibla iwan on the southern side of the mosque was vaulted with muqarnas during the 13th century. The qibla iwan is the only one flanked by two cylindrical minarets. Iwans were also added in stages under the Seljuqs, giving the mosque its current four-iwan form, a type which subsequently became prevalent in Iran and the rest of the Islamic world. Safavid intervention was largely decorative, with the addition of muqarnas, glazed tilework, and minarets flanking the south Qibla iwan.

Linking the four iwans at the center is a large courtyard open to the air, which provides a tranquil space from the hustle and bustle of the city. Brick piers and columns support the roofing system and allow prayer halls to extend away from this central courtyard on each side. The roof of the mosque is a panoply of unusual but charming domes crowning its hypostyle interior.