Answer:The first heroic movement of Iranians took place in 1270 as Tobacco Movement. This movement happened in the follow of accrediting an English company with one of the internal products (Tobacco). Naser Al-Din Shah gave the buy and sell credit of tobacco to an English company in front of a less price. From that time on, the foreign colonization and intervention to the economical affairs of the country started to appear.
The open-minded religious people of the country deprived Shah's decisions and went on a strike. These actions continued until their letters and complaints were delivered to the legal authority, the late Mirza-ye Shirazi. Therefore, the legal authority was informed of the trick in front. The famous authority issued a decree which disrupted all the trends of the enemy.
In this decree, the use and consumption of tobacco was announced as the waging war against the Twelve Imam, the Savior. Therefore, the Qajar Shah had to cancel the contract. Unfortunately, this fighting was not so practical and again the presence of colonization was concrete. From that on, the disastrous trends of colonization began to appear until the Constitutional Movement in 1285.
The main cause of this movement was the establishment of a court and the national council assembly. After a continuous fighting and rioting, they achieved their goals, apparently. However, after some time, the main elements of colonization tied to the Parliament took the control of the country's affairs.
This time, again the hideous appearance of colonization was shown through the influence of those tyrannies and caused so many disasters for the people. This movement was authoritized by Ayatollah Khorasani and Noori and other great scientific and political characters, but instead of being effective, it had the opposite result and paved the way of Qajar dynasty destruction and the appearance of Pahlavi family.
The Pahlavi Regime had the control of the government from the 1299 coup up to 1357 revolution, approximately for 60 years. It imprisoned, murdered and tortured many great characters. It was in the era of Pahlavi Government that Iranian people started their courageous movement with Kashani's leadership and Dr. Mosadegh.
Their movement was mainly for the nationalization of Oil Industry. They were relatively successful in this struggle until the coup of 28 Mordad 1322 which lead to the domination of Pahlavi Regime with the aids of CIA and MOSAD. Mohammad Reza Pahlavi gave the control of Iran's rich sources and natural products to the colonial countries, especially USA, and made the foreigners to be dominant in all the country's affairs.
Analyzing the recent century's events and movements, it can be stated that the three mentioned movements were important in acquiring valuable achievements but they were not considered as the basic or root movements.
In other words, in the three mentioned movements, the root of corruption- the non-religious government under the leadership of a tyrannical person- was preserved and the transformation or any change was done in its appearance, while in the fourth movement of the nation, the root of corruption, the dictatorship government was eradicated and a new revolution and a new system was founded on the previous Regime's ruins.
The fourth revolution was a religious, basic and national revolution which was established by Imam Khomeini's leadership. With Imam's Anti-Tyrannical movement, from Aban 1341, Iran became alive and the people did everything to achieve the Islamic ideals during the 17 years.
The leader of this movement was like a real combatant; he was imprisoned and exiled and lost his dear son in this way. Finally, the faithful Iranian reached the complete victory in the 22nd of Bahman 1357 and opened new horizons of the divine national government for the other nations and governments of the world.