By recent history do you mean the 20th century? or the early modern age?
If there is one historically important time in Iranian history, it was the time of the Saffavid Dynasty around the 16th century- which saw Iran officially adopt Shiism as the state religion. This completed the shift and divide from the majority Sunni dynasties that dominated the Islamic world at the time- from the Mughals in India and Ottomans in Turkey. This sought to give the Iranians a distinct character and showcase their independence from the traditional Arab influenced religious thought on certain matters.
Later, we would see the Iranian Revolution in 1979 overthrow the traditional Iranian monarchy and create the Islamic Republic of Iran- the first state founded upon a religious revolutionary pretext in the middle east for that matter, upon which religious priests or 'Imams' make high level decisions and are privy to the Ayatollah- a saintly figure anointed by god as it were- who is the final say on any matters of political or religious importance.