It is the oldest preserved edifice of its type in Iran and a prototype for later mosque designs throughout Central Asia.
The complex, covering more than 20,000 m2, is also the first Islamic building that adapted the four-courtyard layout of Sassanid palaces to Islamic religious architecture.
Its double-shelled ribbed domes represent an architectural innovation that inspired builders throughout the region.
The site also features remarkable decorative details representative of stylistic developments over more than a thousand years of Islamic art.