The Iwan's Pre-Islamic Origins

The iwan is older than Islam. The form is documented in Parthian palace architecture from the last centuries BCE and reached a monumental scale under the Sasanian Persian empire, most famously in the sixth century Taq Kasra at Ctesiphon, whose brick barrel vault, spanning an enormous unsupported width, remained one of the largest single-span vaults in the world for over a millennium and stood as an acknowledged engineering benchmark for later builders.

Early Islamic architecture in the former Sasanian lands absorbed the iwan directly from this palace tradition, and it entered religious building gradually rather than immediately: early mosques favored the hypostyle hall, and it was under Seljuk patronage from the eleventh century that architects paired the iwan with the mosque courtyard at scale, producing the four-iwan plan that then spread with Seljuk, and later Timurid and Safavid, influence across Iran, Central Asia, Anatolia and the Indian subcontinent. Because the form carried royal and palatial associations from its pre-Islamic origin, its adoption into mosques and madrasas also imported a register of civic grandeur, and iwans remained a preferred element for secular architecture, caravanserais and palace gateways alongside their religious use throughout the medieval and early modern Islamic world.