You don't know enough.
Iran is generally described as being Shiia. Shiaa spiritual leader Ayatollah Khomeini stepped into the political power vacuum created by the descent/death of Shah Reza Pahlavi, at the start of the Iranian Revolution in 1979.
This quick-and-dirty diary does not intend to explore all that convoluted history -- it's Saturday and the sun is shining, and I need sun more than I need mojo. What I do want to say about the uniqueness of Iranian religion is below the fold: