The Safavid dynasty ( ; , ) was one of the most significant ruling dynasties of Persia (modern Iran) after the fall of the Sasanian Empire - following the Muslim conquest of Persia in the seventh century A.D., and "is often considered the beginning of modern Persian history". The Safavid shahs ruled over one of the so-called gunpowder empires, and they ruled one of the greatest Persian empires after the Muslim conquest of Persia and established the Twelver school of Shi'a Islam as the official religion of their empire, marking one of the most important turning points in Muslim history.