Besides its religious significance, Mashhad has played an important political role as well. The Safavid dynasty has been criticized in a book (Red Shi’sm vs. Black Shi’ism) on the perceived dual aspects of the Shi’a religion throughout history) as a period in which although the dynasty didn’t form the idea of Black Shi’ism, but this idea was formed after the defeat of Shah Ismail against the Ottoman leader Sultan Yavuz Selim. Black Shi’ism is a product of the post-Safavid period.