Ruhollah Musavi Khomeini, whose first name means "spirit of Allah", was born on 24 September 1902 in Khomeyn, Markazi Province.
After World War I, arrangements were made for him to study at the Islamic seminary in Esfahan, but he was attracted instead to the seminary in Arak. He was placed under the leadership of Ayatollah Abdul Karim Haeri Yazdi. In 1920, Khomeini moved to Arak and commenced his studies.
His first political book, Kashf al-Asrar (Uncovering of Secrets) published in 1942, was a point-by-point refutation of Asrar-e hazar salih (Secrets of a Thousand Years), a tract written by a disciple of Iran's leading anti-clerical historian.
In January 1963, the Shah announced the "White Revolution", a six-point programme of reform calling for land reform, nationalization of the forests, the sale of state-owned enterprises to private interests, electoral changes to enfranchise women and allow non-Muslims to hold office, profit-sharing in industry, and a literacy campaign in the nation's schools. Some of these initiatives were regarded as dangerous, especially by the powerful and privileged Shi'a ulama (religious scholars), and as Westernizing trends by traditionalists (Khomeini viewed them as "an attack on Islam").
On 22 January 1963 Khomeini issued a strongly worded declaration denouncing the Shah and his plans. Two days later the Shah took an armored column to Qom, and delivered a speech harshly attacking the ulama as a class.
On the afternoon of 'Ashura (3 June 1963), Khomeini delivered a speech at the Feyziyeh madrasah drawing parallels between the Sunni Muslim caliph Yazid, who is perceived as a 'tyrant' by Shias, and the Shah, denouncing the Shah as a "wretched, miserable man," and warning him that if he did not change his ways the day would come when the people would offer up thanks for his departure from the country.
On 5 June 1963 (15 of Khordad) at 3:00 am, two days after this public denunciation of the Shah Mohammad Reza Pahlavi, Khomeini was detained in Qom and transferred to Tehran.
On 26 October 1964, Khomeini denounced both the Shah and the United States. This time it was in response to the "capitulations" or diplomatic immunity granted by the Shah to American military personnel in Iran.
Khomeini spent more than 14 years in exile, mostly in the holy Iraqi city of Najaf. Initially, he was sent to Turkey on 4 November 1964 where he stayed in Bursa in the home of Colonel Ali Cetiner of the Turkish Military Intelligence.
In October 1965, after less than a year, he was allowed to move to Najaf, Iraq, where he stayed until 1978 when he was expelled by then-Vice President Saddam Hussein.
By this time discontent with the Shah was becoming intense and Khomeini visited Neauphle-le-Château, a suburb of Paris, France on a tourist visa on 6 October 1978.
Khomeini was not allowed to return to Iran during the Shah's reign (as he had been in exile). On 16 January 1979, the Shah left the country (ostensibly "on vacation"), never to return.
Two weeks later, on Thursday, 1 February 1979, Khomeini returned in triumph to Iran, welcomed by a joyous crowd estimated (by the BBC) to be of up to five million people.
On 11 February, as revolt spread and armories were taken over, the military declared neutrality and the Bakhtiar regime collapsed.
On 11 February, Khomeini appointed his own competing interim prime minister, Mehdi Bazargan, demanding, "since I have appointed him, he must be obeyed." It was "God's government," he warned, disobedience against him or Bazargan was considered a "revolt against God".
On 30 and 31 March 1979, a referendum to replace the monarchy with an Islamic Republic passed with 98% voting in favour of the replacement, with the question: "should the monarchy be abolished in favour of an Islamic Government?".
On 22 October 1979, the United States admitted the exiled and ailing Shah into the country for cancer treatment. In Iran, there was an immediate outcry, with both Khomeini and leftist groups demanding the Shah's return to Iran for trial and execution.
In November 1979, the new constitution of the Islamic Republic was adopted by national referendum.
On 4 November, a group of Iranian college students calling themselves the Muslim Student Followers of the Imam's Line, took control of the American Embassy in Tehran, holding 52 embassy staff hostage for 444 days – an event known as the Iran hostage crisis.
On 4 February 1980, Abolhassan Banisadr was elected as the first president of Iran.
Iraq launched a full-scale invasion of Iran, beginning the Iran–Iraq War (September 1980 – August 1988).
Khomeini's health declined several years prior to his death. After spending eleven days in Jamaran hospital, Ruhollah Khomeini died on 3 June 1989 after suffering five heart attacks in just ten days, at the age of 86 just before midnight.
Ayatollah Haeri Yazdi transferred to the Islamic seminary in the holy city of Qom, southwest of Tehran, and invited his students to follow.