Sayyid Ruh Allah Musawi Khumayni ,best known as Imam Khomeini, was one the most important Shi'a marja's of the 14th//20th century. He was the leader of the Islamic Revolution in Iran, which won victory in 1979 and overthrew the monarchy and established Islamic Republic in Iran.

He was arrested twice by the monarchical Pahlavi government and was exiled for life in the latter. For a while, he lived in Turkey, then he moved to Najaf. He stayed in Najaf for 13 years teaching, writing and leading the revolutionists in Iran. In 1979, he was forced to leave Iraq; so he went to Paris. After a while, he returned to Iran and led the Islamic Revolution to victory. He was the leader of the Islamic Republic of Iran to the end of his life.

Imam Khomeini's movement doctrine of al-Wilayat al-Mutlaqa li l-Faqih (absolute guardianship of the jurist), a political doctrine based on Shi'a beliefs, is his most important doctrine. He tried to establish the Islamic Republic of Iran and its constitution based on this doctrine.