1. Mohammad Reza Pahlavi faced opposition from Iranian nationalists against Western companies
2. Prime Minister Muhammed Mossadeq led efforts to nationalize the British-owned oil company, leading to a coup supported by Britain and US
3. Shah Pahlavi modernized Iran, but many Iranians felt threatened by this rapid change
4. Grand Ayatollah Ruholla Khomeini emerged as Iran's new leader, establishing an Islamic state based on Shia Islam