The Iranian people were converted to Islam not very much longer after the conquest of the Arab world by Islam, but they refused to adopt the Arabic language, and it's a great point of pride to them that Persian culture and the Persian language and Persian literature survived the conversion to Islam. And the conversion to Islam also was for most of them not the Sunni majority form, but the Shia one. So there's a great discrepancy between Iranian society and many other of what we think of as Arab Muslim States and systems.