The Tarikhaneh is the oldest surviving mosque in Iran, built within a century of the Arab conquest and almost certainly on the foundation of a pre-existing Zoroastrian fire temple. The hypostyle hall is a forest of squat cylindrical brick columns supporting parabolic arches — closer in style to the Sasanian palace at Ctesiphon than to any later Islamic mosque.
The 26-metre minaret to one side is a slightly later Seljuq addition, decorated with bands of brick calligraphy. Free to enter; the surrounding garden is overlooked by the mud-brick walls of the old town.