Great Mosque of Eṣfahān, complex of buildings in Eṣfahān, Iran, that centres on the 11th-century domed sanctuary and includes a second smaller domed chamber, built in 1088, known for its beauty of proportion and design. The central sanctuary was built under the direction of Niẓām al-Mulk, vizier to the Seljuq ruler Malik-Shāh, probably between 1070 and 1075. It stands at the south end of the courtyard. Its large brick dome is supported by 12 heavy piers.
The smaller dome stands at the north end of the courtyard. This single-shelled dome is a structural masterpiece that has survived centuries without damage. The room—made of small gray baked bricks—encloses an area approximately 30 feet (9.1 metres) square and 60 feet (18.2 metres) high. The dome rests on a series of arches, with 16 at the top and one broad arch framed between two narrow ones in each wall at room level. The mosque complex, framed by four huge eyvāns, or vaulted niches, includes structures built at various periods from the 11th century to the 18th—among them, private chapels, a school, a library, and a treasury.