Located at the center of Esfahan—a city full of architectural treasures—is the sprawling Friday Mosque. A mosque has stood on the site since the 8th century, but the oldest elements of the current structure are two domes built during the Seljuk dynasty, which ruled parts of Iran in the 11th century. In the early 12th century the mosque was rebuilt around a rectangular courtyard adjoined on each side by an iwan—a type of hall that opens into a tall arch on one side. The four-iwan design, which first appeared in Esfahan, later became the norm for Iranian mosques
