At least at the political level, the Iranian revival was cut short by the arrivalof the Turks. The Turkish nomads of central Asia, identified in the popularmind with the Turanians of the national history, had been a threat on Iran’snortheastern frontier for several centuries but had been decisively defeatedby the Samanids in a.d. 893. Many of the Turks then began to be broughtinto the Iranian and Islamic world as slaves, to be trained and used primarilyas soldiers. As the Samanid Dynasty lost power, some of these slave-troops,led by their commanders, founded their own independent emirate (knownas the Ghaznavids) in eastern Iran and Afghanistan. Other Turkish tribeswere converted to Islam, often by itinerant mystics (Sufi s), and some of thembegan to migrate into Iran. In a.d. 1040, the Turkish confederation knownas the Saljuqs crushed the Ghaznavids at the Battle of Dandânqân; by a.d.1055, they had reached Baghdad and deposed the last of the Buyids. TheSaljuq chieftain took the title of sultan and claimed to be acting as the temporalagent and protector of the Abbasid caliphate; various territories of theSaljuq Empire were entrusted to direct rule by other members of the family,army officers, and slave-commanders. Some of these eventually broke awayto found their own autonomous dynasties; among them were the descendantsof a Turkish slave who had been appointed governor of Khârazm (a provincenear the Aral Sea). He and his successors took the title Khârazm-shâh,expanded their territory to the east and west, and, in a.d. 1194, defeated thelast of the Saljuq sultans. For more than a century, Turkish warlords thusruled virtually the whole of Iran, and Turks dominated political and militaryaffairs.
The next great incursion by non-Iranian people into Iran was far more catastrophic in its effects. In a.d. 1219, Genghis and the Mongol armies attacked the lands of the Khârazm-shâh ‘Alâ-od-Din Mohammad. Apparently provoked by the execution of some Mongol emissaries, this invasion had the character of a war of revenge: ‘Alâ-od-Din was defeated and chased all across Iran before finally dying on an island in the Caspian. Eastern and northern Iran suffered immensely in the course of this war, with formerly great cities like Marw, Herât, Tus, and Nishâpur reduced to ruins and much of their population massacred or deported. There was a respite after the death of Genghis in a.d. 1227, while the Mongols were preoccupied with other matters, but the campaigns resumed after Genghis’ grandson Hulâgu was commissioned in a.d. 1251 to expand the area under Mongol control and to suppress the efforts then underway by the Isma‘ili religious sect and the Abbasid caliph to organize resistance to the Mongols. Hulâgu crossed into Iran in a.d. 1256, forced the submission of various petty rulers, destroyed the Isma‘ili strongholds, and, in a.d. 1258, captured Baghdad and executed the caliph. The Il-khanids, the dynasty founded by Hulâgu, ruled Iran until a.d. 1335. The Il-khanids were not only ethnically different from the Iranian population, just as the Saljuqs had been, they were also different in religion (favoring Christianity and Buddhism rather than Islam) and tended to look at the people they had conquered with a mixture of disdain and distrust, seeing them as fit only to be exploited like chattel. In general, the Mongols in Iran resisted any cultural assimilation, imposed exorbitant taxes, neglected both agriculture and the traditional system of trade and commerce, and frequently warred with their Muslim neighbors. An attempt in a.d. 1294 to impose the use of paper currency created a fiscal crisis and political upheaval. This ended with the accession in a.d. 1295 of Ghâzân Khân, who declared himself a Muslim and, with the assistance of capable Iranian ministers such as Rashidod-Din, introduced a number of measures to revive the economy and ameliorate conditions for the subject peoples. When the last of the Il-khanids, Abu Sa‘id, died in a.d. 1335, there was no obvious successor to the throne, and the country quickly broke up again into a number of petty principalities ruled by various Turko-Mongol warlords.
A semblance of unity was restored to Iran when its territory was incorporated into the vast empire of the last great Mongol conqueror, Timur Lang (Tamerlane; a.d. 1336–1404). Timur had started out as little more than an adventuresome if talented mercenary with a dubious claim of descent from Genghis, a militant Islamic religious fervor bordering on fanaticism, and an apparently limitless ambition to conquer as his chief assets. In a.d. 1369, with only a small band of followers, he was able to capture Balkh and proclaim himself ruler; by a.d. 1380, he had made himself master of all that part of central Asia known as Transoxiana. He then immediately began a series of campaigns into Iran ( a.d. 1380–88) which added Khorâsân, Sistân, Gorgân, Mâzandarân, Azerbaijan, and Fârs to his realm—only part of a process of empire-building which soon extended to Iraq, Asia Minor, Russia, and India. In Iran, as elsewhere, Timur’s ferocity was unrestrained, as exemplified by his massacre of prisoners in Sistân in a.d. 1384, his reported slaughter of 70,000 people at Isfahan in a.d. 1387, and his treacherous murder of most of the surviving members of the Mozaffarid family (former rulers of Shiraz) in a.d. 1393. Although Timur wanted the vast empire he had created to remain united, it fragmented after his death as his sons and grandsons, whom he had established as governors of various provinces, struggled for parts of it. The bulk of the territory, including almost all of Iran, eventually was ruled by Timur’s fourth son, Shâh Rokh ( a.d. 1377–1447).
The situation in northwestern Iran was more complicated. It had come under the rule of Mirânshâh, Timur’s third son, but his authority was contested by other Timurids and by rival tribes. Even in the days of Timur, the confederation of Turkish tribes known as the Black Sheep (Qara Qoyunlu), which had formerly ruled the area, had proved troublesome. In a.d. 1408, the Black Sheep leader, Qara Yusof, defeated and killed Mirânshâh. As Shâh Rokh moved into western Iran in a.d. 1419, he prepared to attack Qara Yusof, but the latter died before a battle could be engaged. Despite a victory over the Black Sheep army in a.d. 1421, the hold of the Timurids over the region was very tenuous, and Shâh Rokh rather prudently chose to allow Qara Yusof’s descendants to continue to rule as his nominal vassals. Under Jahân Shâh (r. a.d. 1439–67), the Black Sheep principality became a major regional power. Even as the Black Sheep were threatening to eclipse the Timurids, they themselves were coming under attack by another Turkish tribal confederation, the White Sheep (Âq Qoyunlu), led by their ambitious chieftain, Uzun Hasan. Unable to expand to the west because of the rise of the Ottoman Empire, the White Sheep directed their energy eastward against the Black Sheep and the Timurids. In a.d. 1467, Uzun Hasan ambushed Jahân Shâh and took over the Black Sheep capital and territories. Two years later, the Timurid ruler Abu Sa‘id attempted to invade the White Sheep principality but was captured and executed.
For more than four centuries, Iran was thus under the domination of various Turko-Mongol conquerors and rulers. The area suffered much devastation as the result of invasions and warfare. The ethnic makeup of the population was changed considerably by the arrival and settlement of large numbers of Turkomans and, to a lesser degree, Mongols. The fact that so many of these newcomers were tribally organized and nomadic pastoralists also affected the socioeconomic as well as the political balance within this area. Nonetheless, this did not result in anything like the Turkification of Iran, nor did it prevent the continued development of an Iranian culture based on the Persian language. This somewhat paradoxical outcome can be explained by several factors. From the very beginning, the Turko-Mongol military elites were heavily reliant on an Iranian bureaucracy to administer their principalities, and able ministers like the famous Nezâm-ol-Molk under the Saljuqs or Rashid-od-Din under the Mongols influenced state policies and practices in many ways. Moreover, the Samanid system for training Turkish slaves had instilled in them a deep respect for Islamic and Iranian culture. Subsequently, the Turks, and the Mongols after them, also came to accept the norms of this civilization, especially in art and literature, and could even be said to have further stimulated its revival. Even a ruthless warmonger like Timur had a desire to be seen as a glorious and pious king; throughout the Turko-Mongol period, rulers continued to promote trade, to patronize favored religious leaders, to encourage the production of art and literature (especially works of history), and to beautify their capitals. It was thus during this period that a number of famous Iranian poets and scholars lived and when cities such as Isfahan, Tabriz, and Mashhad acquired some of their most impressive architectural jewels.