Why is the majority of Iran Shia?

I don't understand, was Iran Shia due to the overthrowing of Saddam, or was this something that happened way back when due to some other event?

>>7
>>10
>>11
Iran was predominently Shia before the Shah or Ayatollah Khomeini.Saddam was in power long before the American counsulate was taken hostage. Quit trying to rewrite history or at least stick to history outside of living memory.
>>12 I don't even have clue about what your problem is.