See سید روح الله خمینی

Shiite leader Ayatollah Ruholla Khomeini opposed regime of Mohammad Reza Pahlavi, shah; arrested in 1963 and exiled in 1964, he after downfall of 1979 returned to Iran as head of state, and a strict observance of the Islamic code marked his reign.

The western world also knew Sayyid Ruhollah Mūsavi Khomeini as imam, politician, and cleric. He founded the republic of the revolution and saw the overthrow of the last end of the two and a half millennia of Persian monarchy. Following the revolution, the constitution of the republic created the supreme position of the country for as the highest-ranking political and religious authority of the nation, which Khomeini held until his death.
Khomeini, a marja, "source of emulation." of Twelvers a Mujtahid or faqih (an expert in Sharia). He spent more than 15 years. In his writings and preaching, he expanded the theory of welayat-el faqih, the "guardianship of the jurist (clerical authority)," to include theocratic political rule.