Amir Kabir issued an edict banning ornate and excessively formal writing in government documents; the beginning of a modern Persian prose style dates from this time. One of the greatest achievments of Amir Kabir was the building of Dar-ol-Fonoon, the first modern university in Iran.

Dar-ol-Fonoon was established for training a new cadre of administrators and acquainting them with Western techniques. Amir Kabir ordered the school to be built on the edge of the city so it can be expanded as needed. He hired French and Russian instructors as well as Iranians to teach subjects as different as Language, Medicine, Law, Georgraphy, History, Economics, and Engeneering. Unfortunatelly, Amir Kabir did not live long enough to see his greatest monument completed, but it still stands in Tehran as a sign of a great man's ideas for the future of his country. These reforms antagonized various notables who had been excluded from the government. They regarded the Amir Kabir as a social upstart and a threat to their interests, and they formed a coalition against him, in which the queen mother was active. She convinced the young shah that Amir Kabir wanted to usurp the throne. In October 1851 the shah dismissed him and exiled him to Kashan, where he was murdered on the shah's orders.

The Constitutional Revolution
When Naser o-Din Shah was assassinated by Mirza Reza Kermani in 1896, the crown passed to his son Mozaffar o-Din. Mozaffar o-Din Shah was a weak and ineffectual ruler. Royal extravagance and the absence of incoming revenues exacerbated financial problems. The shah quickly spent two large loans from Russia, partly on trips to Europe. Public anger fed on the shah's propensity for granting concessions to Europeans in return for generous payments to him and his officials. People began to demand a curb on royal authority and the establishment of the rule of law as their concern over foreign, and especially Russian, influence grew. The shah's failure to respond to protests by the religious establishment, the merchants, and other classes led the merchants and clerical leaders in January 1906 to take sanctuary from probable arrest in mosques in Tehran and outside the capital. When the shah reneged on a promise to permit the establishment of a "house of justice", or consultative assembly, 10,000 people, led by the merchants, took sanctuary in June in the compound of the British legation in Tehran. In August the shah was forced to issue a decree promising a constitution. In October an elected assembly convened and drew up a constitution that provided for strict limitations on royal power, an elected parliament, or Majles, with wide powers to represent the people, and a government with a cabinet subject to confirmation by the Majles. The shah signed the constitution on December 30, 1906. He died five days later. The Supplementary Fundamental Laws approved in 1907 provided, within limits, for freedom of press, speech, and association, and for security of life and property. The Constitutional Revolution marked the end of the medieval period in Iran. The hopes for constitutional rule were not realized, however. Mohammad Ali Shah (reigned 1907-09), with the aid of Russia, attempted to rescind the constitution and abolish parliamentary government. After several disputes with the members of the Majlis, in June 1908 he used his Russian-officered Persian Cossacks Brigade to bomb the Majlis building, arrest many of the deputies, and close down the assembly.

 Resistance to the shah, however, coalesced in Tabriz, Esfahan, Rasht, and elsewhere. In July 1909, constitutional forces marched from Rasht and Esfahan to Tehran, deposed the shah, and re-established the constitution. The ex-shah went into exile in Russia. Although the constitutional forces had triumphed, they faced serious difficulties. The upheavals of the Constitutional Revolution and civil war had undermined stability and trade. In addition, the ex-shah, with Russian support, attempted to regain his throne, landing troops in July 1910. Most serious of all, the hope that the Constitutional Revolution would inaugurate a new era of independence from the great powers ended when, under the Anglo-Russian Agreement of 1907, Britain and Russia agreed to divide Iran into spheres of influence. The Russians were to enjoy exclusive right to pursue their interests in the northern sphere, the British in the south and east; both powers would be free to compete for economic and political advantage in a neutral sphere in the center. Matters came to a head when Morgan Shuster, a United States administrator hired as treasurer general by the Persian government to reform its finances, sought to collect taxes from powerful officials who were Russian protégés and to send members of the treasury gendarmerie, a tax department police force, into the Russian zone. When in December 1911 the Majles unanimously refused a Russian ultimatum demanding Shuster's dismissal, Russian troops, already in the country, moved to occupy the capital. To prevent this, on December 20 Bakhtiari chiefs and their troops surrounded the Majles building, forced acceptance of the Russian ultimatum, and shut down the assembly, once again suspending the constitution.
There followed a period of government by Bakhtiari chiefs and other powerful notables. Ahmad Shah, was born 21 January 1898 in Tabriz, who succeeded to the throne at age 11, proved to be pleasure loving, effete, and incompetent and was unable to preserve the integrity of Iran or the fate of his dynasty. The occupation of Iran during World War I (1914-18) by Russian, British, and Ottoman troops was a blow from which Ahmad Shah never effectively recovered. With a coup d'état in February 1921, Reza Khan (ruled as Reza Shah Pahlavi, 1925-41) became the preeminent political personality in Iran; Ahmad Shah was formally deposed by the Majles (national consultative assembly) in October 1925 while he was absent in Europe, and that assembly declared the rule of the Qajar dynasty to be terminated. Ahamd Shah died later on 21 February 1930 in Neuilly-sur-Seine, France.