Arba'a Rukun Mosque is one of the oldest Islamic places of worship in the capital. It was built circa 667 (1268/9 AD), concurrently with the Fakr ad-Din Mosque. Arba'a Rukun's mihrab contains an inscription dated from the same year, which commemorates the masjid's late founder, Khusra ibn Mubarak al-Shirazi (Khusrau ibn Muhammed).