The dynasty that ruled Iran from 1501 to 1736 and made it the Shia power it remains today. Its teenage founder Shah Ismail I built the Safavid Empire on the zeal of the Qizilbash cavalry and faith in his own near-divine authority, and imposed Twelver Shia Islam on a largely Sunni land. Ottoman firearms stopped him at Chaldiran in 1514, fixing the Sunni–Shia frontier that persists today. The dynasty peaked under Shah Abbas I, who rebuilt the army, made Isfahan a jewel of Islamic architecture, and tied the empire to the silk trade. Afghan invaders toppled it in 1722; Nadir Shah ended it in 1736.
A boy of fourteen rode into Tabriz in 1501 and announced that he was the rightful king of Iran. He was not bluffing. Shah Ismail led tribal horsemen who believed he was more than a king. To them he was a holy figure, almost divine, the living head of a Sufi brotherhood they would die for. They wore tall red caps and charged his enemies with reckless abandon, certain his blessing made them invincible. Within a decade this boy had conquered a vast realm and begun to impose a new official faith on a largely Sunni land. He decreed that Iran would follow the Shia branch of Islam, breaking with most of the Muslim world around it. That single decision still shapes the country today, more than five hundred years later.