The Safavid conversion of Iran from Sunnism to Shiism took place roughly over the 16th through 18th centuries and made Iran the spiritual bastion of Shia Islam against the onslaughts of Sunni Islam. It made Iran the repository of Persian cultural traditions and self-awareness of Iranianhood, acting as a bridge to modern Iran. It also ensured the dominance of the Twelver sect within Shiism over the Zaydiyyah and Ismaili sects – each of whom had previously experienced their own eras of dominance within Shiism. Through their actions, the Safavids reunified Iran as an independent state in 1501 and established Twelver Shiism as the official religion of their empire, marking one of the most important turning points in the history of Islam.