Muhammed founded the first Islamic state in Medina in 622, establishing the religion of Islam. Islamic art is characterized by aniconism, or the prohibition of images, and calligraphy. Important early Islamic architectural structures include the Dome of the Rock in Jerusalem, notable for housing a sacred rock, and the Selimiye Mosque in Edirne, Turkey, both following a central plan with features like qibla walls oriented towards Mecca and mihrabs. Other mosque styles featured hypostyle halls and four-iwan plans.