History of Iran

Early human migrations in southern and eastern Asia likely included routes through Iran, a region with diverse geography and resources suitable for early hominins. Stone artifacts from gravel deposits along several rivers, including Kashafrud, Mashkid, Ladiz, Sefidrud, Mahabad, and others, indicate the presence of early populations. Key early human occupation sites in Iran are Kashafrud in Khorasan, Mashkid and Ladiz in Sistan, Shiwatoo in Kurdistan, Ganj Par and Darband Cave in Gilan, Khaleseh in Zanjan, Tepe Gakia near Kermanshah,^[1] and Pal Barik in Ilam, dating from one million years ago to 200,000 years ago. Mousterian Stone tools, associated with Neanderthals, have been found across Iran, especially in the Zagros region and central Iran at sites like Kobeh, Kaldar, Bisetun, Qaleh Bozi, Tamtama, Warwasi. A notable discovery was a Neanderthal radius in 1949 by C.S. Coon in Bisitun Cave.^[2]

Upper Paleolithic and Epipaleolithic evidence primarily comes from the Zagros region, with sites in Kermanshah and Khoramabad like Yafteh Cave. In 2018, a Neanderthal child's tooth was found in Kermanshah, alongside Middle Paleolithic tools.^[3] The Epipaleolithic period, spanning c. 18,000 to 11,000 BCE, saw hunter-gatherers living in Zagros Mountains caves, with an increased variety of hunted and collected plants and animals, including smaller vertebrates, pistachios, wild fruit, snails, and small aquatic animals.

Before the emergence of Iranian peoples during the Early Iron Age, the Iranian plateau hosted numerous ancient civilizations. The Early Bronze Age witnessed urbanization into city-states and the invention of writing in the Near East. Susa, one of the world's oldest settlements, was founded around 4395 BCE,^[4] soon after the Sumerian city of Uruk in 4500 BCE. Archaeologists believe Susa was influenced by Uruk, incorporating many aspects of Mesopotamian culture.^[5] Susa later became the capital of Elam, founded around 4000 BCE.^[4]

Elam, centered in western and southwestern Iran, was a significant ancient civilization extending into southern Iraq. Its name, Elam, derives from Sumerian and Akkadian translations. Elam was a leading political force in the Ancient Near East, known as Susiana in classical literature, after its capital Susa. Elam's culture influenced the Persian Achaemenid dynasty, and the Elamite language, considered a language isolate, was used officially during that period. The Elamites are thought to be ancestors of the modern Lurs, whose language, Luri, diverged from Middle Persian.

Additionally, the Iranian plateau contains numerous prehistoric sites, indicating the presence of ancient cultures and urban settlements in the fourth millennium BCE.^[6] Parts of what is now northwestern Iran were once part of the Kura-Araxes culture (circa 3400 BCE - ca. 2000 BCE), extending into the Caucasus and Anatolia.^[7] The Jiroft culture in southeastern Iran is among the earliest on the plateau. Jiroft is a significant archaeological site with many 4th millennium BCE artifacts, featuring unique engravings of animals, mythological figures, and architectural motifs. These artifacts, made from materials like chlorite, copper, bronze, terracotta, and lapis lazuli, suggest a rich cultural heritage.

Russian historian Igor M. Diakonoff emphasized that modern Iranians primarily descend from non-Indo-European groups, specifically the pre-Iranic inhabitants of the Iranian Plateau, rather than Proto-Indo-European tribes.^[8]

The Proto-Iranians, a branch of the Indo-Iranians, emerged in Central Asia around the mid-2nd millennium BCE.^[9] This era marked the distinction of the Iranian peoples, who expanded over a vast region, including the Eurasian Steppe, from the Danubian plains in the west to the Ordos Plateau in the east and the Iranian Plateau in the south​.^[10]

The historical records become clearer with the Neo-Assyrian Empire's accounts of interactions with tribes from the Iranian plateau. This influx of Iranians led to the Elamites losing territories and retreating to Elam, Khuzestan, and nearby areas.^[11] Bahman Firuzmandi suggested that southern Iranians might have mixed with the Elamite populations in these regions.^[12] In the early centuries of the first millennium BCE, ancient Persians, established in the western Iranian Plateau. By the mid-first millennium BCE, ethnic groups such as the Medes, Persians, and Parthians were present on the Iranian plateau, but they remained under Assyrian control like much of the Near East until the Medes rose to prominence. During this period, parts of what is now Iranian Azerbaijan were part of Urartu. The emergence of significant historical empires like the Medes, the Achaemenid, Parthian, and Sasanian Empires marked the beginning of the Iranian Empire in the Iron Age.

The Medes were an ancient Iranian people who spoke Median and inhabited Media, an area spanning western to northern Iran. They settled in northwestern Iran and parts of Mesopotamia around Ecbatana (modern-day Hamadan) circa the 11th century BCE. Their consolidation in Iran is believed to have occurred in the 8th century BCE. By the 7th century BCE, the Medes had established control over western Iran and possibly other areas, though the exact extent of their territory is unclear.

Despite their significant role in ancient Near Eastern history, the Medes left no written records. Their history is primarily known through foreign sources, including Assyrian, Babylonian, Armenian, and Greek accounts, as well as from Iranian archaeological sites believed to be Median. Herodotus depicted the Medes as a powerful people who established an empire in the early 7th century BCE, lasting until the 550s BCE.

In 646 BCE, Assyrian king Ashurbanipal sacked Susa, ending Elamite dominance in the region.^[13] For over 150 years, Assyrian kings from Northern Mesopotamia had sought to conquer the Median tribes of Western Iran.^[14] Facing Assyrian pressure, small kingdoms on the western Iranian plateau merged into larger, more centralized states. During the latter half of the 7th century BCE, the Medes achieved independence under the leadership of Deioces. In 612 BCE, Cyaxares, Deioces' grandson, allied with Babylonian king Nabopolassar to invade Assyria. This alliance culminated in the siege and destruction of Nineveh, the Assyrian capital, leading to the fall of the Neo-Assyrian Empire.^[15] The Medes also conquered and dissolved Urartu.^[16] The Medes are recognized for founding the first Iranian empire and nation, which was the largest of its time until Cyrus the Great merged the Medes and Persians, forming the Achaemenid Empire around 550–330 BCE. Media became a significant province under successive empires, including the Achaemenids, Seleucids, Parthians, and Sasanians.

The Achaemenid Empire, founded by Cyrus the Great in 550 BCE, was based in what is now Iran and became the largest empire of its time, covering 5.5 million square kilometers. It extended from the Balkans and Egypt in the west, across West Asia, Central Asia, and into the Indus Valley in South Asia.^[17]

Originating in Persis, southwestern Iran, around the 7th century BCE, the Persians,^[18] under Cyrus, overthrew the Median, Lydian, and Neo-Babylonian Empires. Cyrus was noted for his benign governance, which contributed to the empire's longevity, and was titled "King of Kings" (shāhanshāh). His son, Cambyses II, conquered Egypt, but died amidst mysterious circumstances, leading to Darius I’s rise to power after overthrowing Bardiya.

Darius I established administrative reforms, built extensive infrastructure like roads and canals, and standardized coinage. The Old Persian language was used in royal inscriptions. Under Cyrus and Darius, the empire became the largest in history up to that point, known for its tolerance and respect for other cultures.^[19]

In the late sixth century BCE, Darius extended the empire into Europe, subduing regions including Thrace and making Macedon a vassal state around 512/511 BCE.^[20] However, the empire faced challenges in Greece. The Greco-Persian Wars began in the early 5th century BCE following a revolt in Miletus supported by Athens. Despite early successes, including the capture of Athens, the Persians were eventually defeated and withdrew from Europe.^[21]

The empire's decline began with internal strife and external pressures. Egypt gained independence in 404 BCE after Darius II's death but was reconquered in 343 BCE by Artaxerxes III. The Achaemenid Empire ultimately fell to Alexander the Great in 330 BCE, marking the start of the Hellenistic period and the rise of the Ptolemaic Kingdom and Seleucid Empire as successors.

In the modern era, the Achaemenid Empire is acknowledged for establishing a successful model of centralized, bureaucratic administration. This system was characterized by its multicultural policy, which included the construction of complex infrastructures like road systems and an organized postal service. The empire also promoted the use of official languages across its vast territories and developed extensive civil services, including a large, professional army. These advancements were influential, inspiring similar governance styles in various empires that followed.^[22]

The Seleucid Empire, a Greek power in West Asia during the Hellenistic period, was established in 312 BCE by Seleucus I Nicator, a Macedonian general. This empire emerged following the division of Alexander the Great's Macedonian Empire and was ruled by the Seleucid dynasty until its annexation by the Roman Republic in 63 BCE. Seleucus I initially received Babylonia and Assyria in 321 BCE and expanded his territory to include modern-day Iraq, Iran, Afghanistan, Syria, Lebanon, and parts of Turkmenistan, regions once controlled by the Achaemenid Empire. At its peak, the Seleucid Empire also encompassed Anatolia, Persia, the Levant, Mesopotamia, and modern Kuwait.

The Seleucid Empire was a significant center of Hellenistic culture, promoting Greek customs and language while generally tolerating local traditions. A Greek urban elite dominated its politics, supported by Greek immigrants. The empire faced challenges from Ptolemaic Egypt in the west and lost significant territory to the Maurya Empire in the east under Chandragupta in 305 BCE.

In the early 2nd century BCE, Antiochus III the Great's efforts to extend Seleucid influence into Greece were countered by the Roman Republic, leading to the loss of territories west of the Taurus Mountains and significant war reparations. This marked the beginning of the empire's decline. Parthia, under Mithridates I, seized much of its eastern lands in the mid-2nd century BCE, while the Greco-Bactrian Kingdom thrived in the northeast. Antiochus' aggressive Hellenizing (or de-Judaizing) activities provoked a full scale armed rebellion in Judea—the Maccabean Revolt. Efforts to deal with both the Parthians and the Jews as well as retain control of the provinces at the same time proved beyond the weakened empire's power. Reduced to a smaller state in Syria, the Seleucids were eventually conquered by Tigranes the Great of Armenia in 83 BCE and finally by the Roman general Pompey in 63 BCE.

The Parthian Empire, a major Iranian power, existed from 247 BCE to 224 CE.^[23] Founded by Arsaces I,^[24] leader of the Parni tribe,^[25] it began in Parthia in northeast Iran, initially a satrapy rebelling against the Seleucid Empire. The empire expanded significantly under Mithridates I (r. c. 171 – 132 BCE), who captured Media and Mesopotamia from the Seleucids. At its zenith, the Parthian Empire stretched from today's central-eastern Turkey to Afghanistan and western Pakistan. It was a crucial trade hub on the Silk Road, linking the Roman Empire and the Han dynasty of China.

The Parthians integrated various cultural elements into their empire, including Persian, Hellenistic, and regional influences in art, architecture, religion, and royal insignia. Initially adopting Greek cultural aspects, the Arsacid rulers, who styled themselves as "King of Kings," gradually revived Iranian traditions. Unlike the central administration of the Achaemenids, the Arsacids often accepted local kings as vassals, appointing fewer satraps, mainly outside Iran. The empire's capital eventually moved from Nisa to Ctesiphon, near modern Baghdad.

Parthia's early adversaries included the Seleucids and Scythians. Expanding westward, conflicts arose with the Kingdom of Armenia and later the Roman Republic. Parthia and Rome vied for influence over Armenia. Significant battles against Rome included the Battle of Carrhae in 53 BCE and capturing Levant territories in 40–39 BCE. However, internal civil wars posed a greater threat than foreign invasion. The empire collapsed when Ardashir I, a ruler in Persis, revolted, overthrowing the last Arsacid ruler, Artabanus IV, in 224 CE, and establishing the Sasanian Empire.

Parthian historical records are limited compared to Achaemenid and Sasanian sources. Known mostly through Greek, Roman, and Chinese histories, Parthian history is also pieced together from cuneiform tablets, inscriptions, coins, and some parchment documents. Parthian art also provides valuable insights into their society and culture.^[26]

The Sasanian Empire, founded by Ardashir I, was a prominent power for over 400 years, rivaling the Roman and later Byzantine Empires. At its peak, it covered modern Iran, Iraq, Azerbaijan, Armenia, Georgia, parts of Russia, Lebanon, Jordan, Palestine, Israel, parts of Afghanistan, Turkey, Syria, Pakistan, Central Asia, Eastern Arabia, and parts of Egypt.^[27]

The empire's history was marked by frequent wars with the Byzantine Empire, a continuation of the Roman-Parthian Wars. These wars, starting in the 1st century BCE and lasting until the 7th century CE, are considered the longest-lasting conflicts in human history. A notable victory for the Persians was at the Battle of Edessa in 260, where Emperor Valerian was captured.

Under Khosrow II (590–628), the empire expanded, annexing Egypt, Jordan, Palestine, and Lebanon, and was known as Erânshahr ("Dominion of the Aryans").^[28] The Sasanians clashed with the Romano-Byzantine armies over Anatolia, the Caucasus, Mesopotamia, Armenia, and the Levant. An uneasy peace was established under Justinian I through tribute payment.

However, conflicts resumed following the deposition of Byzantine Emperor Maurice, leading to several battles and eventually a peace settlement. The Roman-Persian Wars concluded with the Byzantine–Sasanian War of 602–628, culminating in the siege of Constantinople. The Sasanian Empire fell to the Arab Conquest at the Battle of al-Qādisiyyah in 632, marking the empire's end.

The Sasanian period, considered highly influential in Iranian history, greatly impacted world civilization. This era saw the peak of Persian culture and influenced Roman civilization, with its cultural reach extending to Western Europe, Africa, China, and India. It played a significant role in shaping medieval European and Asiatic art.

The Sasanian dynasty's culture profoundly influenced the Islamic world, transforming the Islamic conquest of Iran into a Persian Renaissance. Many aspects of what later became Islamic culture, including architecture, writing, and other contributions, were derived from the Sasanians.

The Muslim conquest of Persia, also known as the Arab conquest of Iran,^[29] occurred between 632 and 654 CE, leading to the fall of the Sasanian Empire and the decline of Zoroastrianism. This period coincided with significant political, social, economic, and military turmoil in Persia. The once powerful Sasanian Empire was weakened by prolonged warfare against the Byzantine Empire and internal political instability, particularly following Shah Khosrow II's execution in 628 and the subsequent enthronement of ten different claimants in four years.

The Arab Muslims, under the Rashidun Caliphate, initially invaded Sasanian territory in 633, with Khalid ibn al-Walid attacking the key province of Asōristān (modern Iraq). Despite initial setbacks and Sasanian counterattacks, the Muslims achieved a decisive victory at the Battle of al-Qadisiyyah in 636 under Sa'd ibn Abi Waqqas, leading to the loss of Sasanian control west of Iran. The Zagros Mountains served as a border between the Rashidun Caliphate and the Sasanian Empire until 642, when Caliph Umar ibn al-Khattab ordered a full-scale invasion, resulting in the complete conquest of the Sasanian Empire by 651.^[30]

Despite the rapid conquest, Iranian resistance to the Arab invaders was significant. Many urban centers, except in regions like Tabaristan and Transoxiana, fell to Arab control by 651. Numerous cities rebelled, killing Arab governors or attacking garrisons, but Arab reinforcements eventually suppressed these uprisings, establishing Islamic control. The Islamization of Iran was a gradual process, incentivized over centuries. Despite violent resistance in some areas, the Persian language and Iranian culture persisted, with Islam becoming the dominant religion by the late Middle Ages.^[31]

Following the fall of the Sasanian Empire in 651, the Umayyad Caliphate, which emerged as the ruling power, adopted many Persian customs, especially in administration and court culture. Provincial governors during this period were often Persianized Arameans or ethnic Persians. Persian remained the official language of the caliphate's business until the end of the 7th century, when Arabic gradually replaced it, evidenced by the Arabic script replacing Pahlavi on coinage starting in 692 in Damascus.^[32]

The Umayyad regime enforced Arabic as the primary language in its territories, often forcefully. Al-Hajjaj ibn Yusuf, disapproving of the widespread use of Persian, ordered the replacement of local languages with Arabic, sometimes by force.^[33] This policy included the destruction of non-Arabic cultural and historical records, as described by al-Biruni regarding the conquest of Khwarazmia.

The Umayyads also established the "dhimmah" system, taxing non-Muslims ("dhimmis") more heavily, partly to benefit the Arab Muslim community financially and discourage conversions to Islam, as conversions could decrease tax revenues. During this time, non-Arab Muslims, like the Persians, were considered mawali ("clients") and faced second-class treatment. The Umayyad policies towards non-Arab Muslims and Shias created unrest among these groups.

Not all of Iran was under Arab control during this period. Regions like Daylam, Tabaristan, and the Mount Damavand area remained independent. The Dabuyids, especially Farrukhan the Great (r. 712–728), successfully resisted Arab advances in Tabaristan.

The Umayyad Caliphate's decline began with the death of Caliph Hisham ibn Abd al-Malik in 743, leading to civil war. Abu Muslim, sent by the Abbasid Caliphate to Khorasan, played a key role in the Abbasid revolt. He conquered Merv and effectively controlled Khorasan. Concurrently, Dabuyid ruler Khurshid declared independence but soon acknowledged Abbasid authority. The Umayyads were ultimately defeated by the Abbasids at the Battle of the Zab in 750, leading to the storming of Damascus and the end of the Umayyad Caliphate.

The Abbasid Revolution in 750 CE,^[34] led by the Iranian general Abu Muslim Khorasani, marked a significant shift in the Islamic empire. The Abbasid army, comprising both Iranians and Arabs, overthrew the Umayyad Caliphate, signaling the end of Arab dominance and the beginning of a more inclusive, multi-ethnic state in the Middle East.^[35]

One of the Abbasids' first actions was to move the capital from Damascus to Baghdad,^[36] founded in 762 on the Tigris River in a region influenced by Persian culture. This move was partly in response to demands from Persian mawali, who sought reduced Arab influence. The Abbasids introduced the role of vizier in their administration, a position similar to a vice-caliph, which led to many caliphs adopting more ceremonial roles. This change, along with the rise of a new Persian bureaucracy, marked a clear departure from the Umayyad era.

By the 9th century, the Abbasid Caliphate's control weakened as regional leaders emerged, challenging its authority.^[36] The caliphs began employing Mamluks, Turkic-speaking warriors, as slave soldiers. Over time, these mamluks gained significant power, eventually overshadowing the caliphs.^[34]

This period also saw uprisings like the Khurramite movement, led by Babak Khorramdin in Azerbaijan, advocating for Persian independence and a return to the pre-Islamic Iranian glory. This movement lasted over twenty years before its suppression.^[37]

Various dynasties rose in Iran during the Abbasid period, including the Tahirids in Khorasan, the Saffarids in Sistan, and the Samanids, who extended their rule from central Iran to Pakistan.^[34]

In the early 10th century, the Buyid dynasty, a Persian faction, gained substantial power in Baghdad, effectively controlling the Abbasid administration. The Buyids were later defeated by the Seljuq Turks, who maintained nominal allegiance to the Abbasids until the Mongol invasion in 1258, which ended the Abbasid dynasty.^[36]

The Abbasid era also saw the empowerment of non-Arab Muslims (mawali) and a shift from an Arab-centric empire to a Muslim empire. Around 930 CE, a policy was introduced requiring all empire bureaucrats to be Muslim.

The Iranian Intermezzo, a term often overshadowed in the annals of history, refers to an epochal period spanning from 821 to 1055 CE. This era, nestled between the decline of the Abbasid Caliphate's rule and the rise of the Seljuk Turks, marked a resurgence of Iranian culture, the rise of native dynasties, and significant contributions to the Islamic Golden Age.

The Dawn of the Iranian Intermezzo (821 CE)

The Iranian Intermezzo commences with the decline of the Abbasid Caliphate’s control over the Iranian plateau. This power vacuum paved the way for local Iranian leaders to establish their dominions.

The Tahirid Dynasty (821-873 CE)

Founded by Tahir ibn Husayn, the Tahirids were the first independent dynasty to rise in the era. Although they acknowledged the Abbasid Caliphate's religious authority, they ruled independently in Khurasan. The Tahirids are noted for fostering an environment where Persian culture and language began to flourish after Arab rule.

The Saffarid Dynasty (867-1002 CE)

Yaqub ibn al-Layth al-Saffar, a coppersmith turned military leader, founded the Saffarid dynasty. His conquests extended across the Iranian plateau, marking a significant expansion of Iranian influence.

The Samanid Dynasty (819-999 CE)

Perhaps the most culturally influential were the Samanids, under whom Persian literature and art saw a remarkable revival. Notable figures like Rudaki and Ferdowsi flourished, with Ferdowsi’s “Shahnameh” exemplifying the renaissance of Persian culture.

The Rise of the Buyids (934-1055 CE)

The Buyid dynasty, founded by Ali ibn Buya, marked the peak of the Iranian Intermezzo. They effectively controlled Baghdad by 945 CE, reducing the Abbasid caliphs to figureheads. Under the Buyids, Persian culture, science, and literature reached new heights.

The Ghaznavid Dynasty (977-1186 CE)

Founded by Sabuktigin, the Ghaznavid dynasty is renowned for its military conquests and cultural achievements. Mahmud of Ghazni, a prominent Ghaznavid ruler, expanded the dynasty's territories and patronized arts and literature.

The Culmination: Arrival of the Seljuks (1055 CE)

The Iranian Intermezzo concluded with the ascendancy of the Seljuk Turks. Tughril Beg, the first Seljuk ruler, overthrew the Buyids in 1055 CE, ushering in a new era in Middle Eastern history.

The Iranian Intermezzo was a watershed period in Middle Eastern history. It witnessed the revival of Persian culture, significant political changes, and remarkable achievements in arts, science, and literature. This era not only shaped the identity of modern Iran but also contributed extensively to the Islamic Golden Age.

In 977 CE, Sabuktigin, a Turkic governor under the Samanids, established the Ghaznavid dynasty in Ghazna (modern-day Afghanistan), which lasted until 1186.^[34] The Ghaznavids expanded their empire by annexing Samanid territories south of the Amu Darya in the late 10th century, eventually occupying parts of Eastern Iran, Afghanistan, Pakistan, and north-west India.The Ghaznavids are credited with introducing Islam to predominantly Hindu India, initiated by ruler Mahmud's invasions starting in 1000. However, their power in the region waned, especially after Mahmud's death in 1030, and by 1040, the Seljuqs had overtaken Ghaznavid lands in Iran.^[36]

The Seljuqs, of Turkic origin and Persianate culture, conquered Iran during the 11th century.^[34] They established the Sunni Muslim Great Seljuq Empire, extending from Anatolia to western Afghanistan and the borders of modern-day China. Known as cultural patrons, they significantly influenced Persian art, literature, and language, and are seen as the cultural forebears of the Western Turks.

Tughril Beg, the founder of the Seljuq dynasty, initially targeted the Ghaznavids in Khorasan and expanded his empire without destroying conquered cities. In 1055, he was recognized as King of the East by the Baghdad caliph. Under his successor, Malik Shah (1072–1092), and his Iranian vizier, Nizam al Mulk, the empire experienced a cultural and scientific renaissance. This period saw the establishment of an observatory where Omar Khayyám worked and the founding of religious schools.^[34]

After Malik Shah I's death in 1092, the Seljuq Empire fragmented due to internal disputes among his brother and sons. This fragmentation led to the formation of different states, including the Sultanate of Rûm in Anatolia and various dominions in Syria, Iraq, and Persia. The weakening of Seljuq power in Iran paved the way for the rise of other dynasties, including a revitalized Abbasid caliphate and the Khwarezmshahs, a Sunni Muslim Persianate dynasty of East Turkic origin. In 1194, the Khwarezmshah Ala ad-Din Tekish defeated the last Seljuq sultan, leading to the collapse of the Seljuq Empire in Iran, except for the Sultanate of Rûm.

The Khwarazmian dynasty, established in Iran, lasted only until the Mongol invasion under Genghis Khan. By 1218, the rapidly expanding Mongol Empire bordered the Khwarazmian territory. Ala ad-Din Muhammad, the Khwarazmian ruler, had expanded his realm across most of Iran and declared himself shah, seeking recognition from the Abbasid caliph Al-Nasir, which was denied.

The Mongol invasion of Iran began in 1219 after his diplomatic missions to Khwarezm were massacred. The invasion was brutal and comprehensive; major cities like Bukhara, Samarkand, Herat, Tus, and Nishapur were destroyed, and their populations were massacred. Ala ad-Din Muhammad fled and eventually died on an island in the Caspian Sea.

During this invasion, the Mongols employed advanced military techniques, including the use of Chinese catapult units and possibly gunpowder bombs. Chinese soldiers, skilled in gunpowder technology, were part of the Mongol army. The Mongol conquest is believed to have introduced Chinese gunpowder weapons, including the huochong (a mortar), to Central Asia. Subsequent local literature depicted gunpowder weapons similar to those used in China.

The Mongol invasion, culminating in Genghis Khan's death in 1227, was devastating for Iran. It resulted in significant destruction, including the pillaging of cities in western Azerbaijan. The Mongols, despite later converting to Islam and assimilating into Iranian culture, inflicted irreparable damage. They destroyed centuries of Islamic scholarship, culture, and infrastructure, razing cities, burning libraries, and replacing mosques with Buddhist temples in some areas.^[38]

The invasion also had a catastrophic impact on Iranian civilian life and the country's infrastructure. The destruction of qanat irrigation systems, particularly in northeastern Iran, disrupted the pattern of settlements, leading to the abandonment of many once-prosperous agricultural towns.^[39]

Following Genghis Khan's death, Iran was governed by various Mongol commanders. Hulagu Khan, Genghis' grandson, was responsible for further westward expansion of Mongol power. By his time, however, the Mongol Empire had fragmented into different factions. Hulagu established the Ilkhanate in Iran, a breakaway state of the Mongol Empire, which ruled for eighty years and became increasingly Persianized.

In 1258, Hulagu seized Baghdad and executed the last Abbasid caliph. His expansion was halted at the Battle of Ain Jalut in Palestine in 1260 by the Mamelukes. Additionally, Hulagu's campaigns against Muslims caused conflict with Berke, the Muslim khan of the Golden Horde, highlighting the disintegration of Mongol unity.

Under Ghazan (r. 1295–1304), Hulagu's great-grandson, Islam was established as the state religion of the Ilkhanate. Ghazan, along with his Iranian vizier Rashid al-Din, initiated an economic revival in Iran. They reduced taxes for artisans, promoted agriculture, restored irrigation works, and enhanced trade route security, leading to a surge in commerce.

These developments facilitated cultural exchanges across Asia, enriching Iranian culture. A notable outcome was the emergence of a new style of Iranian painting, blending Mesopotamian and Chinese artistic elements. However, after the death of Ghazan's nephew Abu Said in 1335, the Ilkhanate descended into civil war and fragmented into several smaller dynasties, including the Jalayirids, Muzaffarids, Sarbadars, and Kartids.

The 14th century also witnessed the devastating impact of the Black Death, which killed approximately 30% of Iran's population.^[40]

Iran experienced a period of division until Timur, a Turco-Mongol leader of the Timurid dynasty, emerged. The Timurid Empire, part of the Persianate world, was established after Timur conquered most of Iran following his invasion that began in 1381. Timur's military campaigns were marked by exceptional brutality, including widespread slaughter and the destruction of cities.^[41]

Despite his regime's tyrannical and violent nature, Timur included Iranians in administrative roles and promoted architecture and poetry. The Timurid dynasty maintained control over most of Iran until 1452, when they lost the majority of their territory to the Black Sheep Turkmen. The Black Sheep Turkmen were later defeated by the White Sheep Turkmen led by Uzun Hasan in 1468, who then ruled Iran until the rise of the Safavids.^[41]

The era of the Timurids was significant for Persian literature, particularly for the Sufi poet Hafez. His popularity and the widespread copying of his divan were firmly established during this period. Despite the persecution Sufis faced from orthodox Muslims, who often deemed their teachings blasphemous, Sufism thrived, developing a rich symbolic language filled with metaphors to disguise potentially controversial philosophical ideas. Hafez, while concealing his Sufi beliefs, adeptly utilized this symbolic language in his poetry, earning recognition for perfecting this form.^[42] His work influenced other poets, including Jami, whose popularity extended throughout the Persianate world.^[43]

The Safavid dynasty, ruling from 1501 to 1722 with a brief restoration from 1729 to 1736, is often seen as the commencement of modern Persian history. They established the Twelver school of Shi'a Islam as the state religion, a pivotal event in Muslim history. At their height, the Safavids controlled modern Iran, Azerbaijan, Armenia, Georgia, parts of the Caucasus, Iraq, Kuwait, Afghanistan, and parts of Turkey, Syria, Pakistan, Turkmenistan, and Uzbekistan, making them one of the major Islamic "gunpowder empires" alongside the Ottoman and Mughal Empires.^[44]

Founded by Ismāil I, who became Shāh Ismāil^[45] after capturing Tabriz in 1501, the Safavid dynasty emerged victorious in the power struggle that ensued in Persia after the disintegration of the Kara Koyunlu and the Aq Qoyunlu. Ismāil swiftly consolidated his rule over all of Persia.

The Safavid era saw significant administrative, cultural, and military developments. The dynasty's rulers, notably Shah Abbas I, implemented substantial military reforms with the help of European experts like Robert Shirley, strengthened commercial ties with European powers, and revitalized Persian architecture and culture. Shah Abbas I also pursued a policy of deporting and resettling large numbers of Circassians, Georgians, and Armenians within Iran, partly to reduce the power of the Qizilbash tribal elite.^[46]

However, many Safavid rulers after Abbas I were less effective, indulging in leisurely pursuits and neglecting state affairs, leading to the dynasty's decline. This decline was exacerbated by external pressures, including raids by neighboring powers. In 1722, Mir Wais Khan, a Ghilzai Pashtun chieftain, revolted in Kandahar, and Peter the Great of Russia capitalized on the chaos to seize Persian territories. The Afghan army, led by Mahmud, Mir Wais' son, captured Isfahan and proclaimed a new rule. The Safavid dynasty effectively ended amid this turmoil, and in 1724, Iran's territories were divided between the Ottomans and the Russians under the Treaty of Constantinople.^[47] Iran's contemporary Shia character, and significant segments of Iran's current borders take their origin from this era.

Prior to the rise of the Safavid Empire, Sunni Islam was the dominant religion, accounting for around 90% of the population at the time.^[53] During the 10th and 11th centuries, Fatimids sent Ismailis Da'i (missioners) to Iran as well as other Muslim lands. When Ismailis divided into two sects, Nizaris established their base in Iran. After the Mongol raid in 1256 and fall of the Abbasids, Sunni hierarchies faltered. Not only did they lose the caliphate but also the status of official madhhab. Their loss was the gain of Shia, whose centre wasn't in Iran at that time. The main change occurred in the beginning of the 16th century, when Ismail I founded the Safavid dynasty and initiated a religious policy to recognize Shi'a Islam as the official religion of the Safavid Empire, and the fact that modern Iran remains an officially Shi'ite state is a direct result of Ismail's actions. According to Mortaza Motahhari the majority of Iranian scholars and masses remained Sunni until the time of the Safavids.

Iran's territorial integrity was restored by Nader Shah, a native Iranian Turkic warlord from Khorasan. He rose to prominence by defeating the Afghans, pushing back the Ottomans, reinstating the Safavids, and negotiating the withdrawal of Russian forces from Iranian Caucasian territories through the Treaty of Resht and Treaty of Ganja. By 1736, Nader Shah had become powerful enough to depose the Safavids and declare himself shah. His empire, one of the last great conquests of Asia, was briefly among the world's most powerful.

To finance his wars against the Ottoman Empire, Nader Shah targeted the wealthy but vulnerable Mughal Empire to the east. In 1739, with his loyal Caucasian subjects, including Erekle II, Nader Shah invaded Mughal India. He achieved a remarkable victory by defeating a larger Mughal army in less than three hours. Following this triumph, he sacked and looted Delhi, acquiring immense wealth that he brought back to Persia.^[48] He also subjugated the Uzbek khanates and reinstated Persian rule over vast regions, including the entire Caucasus, Bahrain, and parts of Anatolia and Mesopotamia. However, his defeat in Dagestan, marked by guerrilla warfare and a significant military loss, signaled a turning point in his career. Nader's later years were marked by growing paranoia, cruelty, and the eventual provocation of revolts, leading to his assassination in 1747.^[49]

Following Nader's death, Iran plunged into anarchy as various military commanders vied for control. The Afsharids, Nader's dynasty, were soon confined to Khorasan. The Caucasian territories fragmented into various khanates, and the Ottomans, Omanis, and Uzbeks regained lost territories. Ahmad Shah Durrani, a former officer of Nader, founded what became modern Afghanistan.

Georgian rulers Erekle II and Teimuraz II, appointed by Nader, capitalized on the instability, declaring de facto independence and unifying eastern Georgia.^[50] This period also saw the rise of the Zand dynasty under Karim Khan,^[51] who established a realm of relative stability in Iran and parts of the Caucasus. However, following Karim Khan's death in 1779, Iran descended into another civil war, leading to the rise of the Qajar dynasty. During this period, Iran permanently lost Basra to the Ottomans and Bahrain to the Al Khalifa family after the Bani Utbah invasion in 1783.^[52]

Agha Mohammad Khan, after emerging victorious from the civil war following the last Zand king's demise, focused on reuniting and centralizing Iran.^[54] Post-Nader Shah and the Zand era, Iran's Caucasian territories had formed various khanates. Agha Mohammad Khan aimed to reincorporate these regions into Iran, considering them as integral as any mainland territory.

One of his primary targets was Georgia, which he viewed as crucial to Iranian sovereignty. He demanded that the Georgian king, Erekle II, renounce his 1783 treaty with Russia and reaccept Persian suzerainty, which Erekle II refused. In response, Agha Mohammad Khan launched a military campaign, successfully reasserting Iranian control over various Caucasian territories, including modern-day Armenia, Azerbaijan, Dagestan, and Igdir. He triumphed in the Battle of Krtsanisi, leading to the capture of Tbilisi and the effective resubjugation of Georgia.^[55]

In 1796, after returning from his successful campaign in Georgia and transporting thousands of Georgian captives to Iran, Agha Mohammad Khan was formally crowned Shah. His reign was cut short by assassination in 1797 while planning another expedition against Georgia. Following his death, Russia capitalized on the regional instability. In 1799, Russian forces entered Tbilisi, and by 1801, they had effectively annexed Georgia. This expansion marked the beginning of the Russo-Persian Wars (1804-1813 and 1826–1828), leading to the eventual cession of eastern Georgia, Dagestan, Armenia, and Azerbaijan to Russia, as stipulated in the Treaties of Gulistan and Turkmenchay. Thus, the territories north of the Aras River, including contemporary Azerbaijan, eastern Georgia, Dagestan, and Armenia, remained part of Iran until their 19th-century occupation by Russia.^[56]

Following the Russo-Persian Wars and the official loss of vast territories in the Caucasus, significant demographic shifts occurred. The wars of 1804–1814 and 1826–1828 led to large migrations known as Caucasian Muhajirs to mainland Iran. This movement included various ethnic groups such as Ayrums, Qarapapaqs, Circassians, Shia Lezgins, and other Transcaucasian Muslims.^[57] Post the Battle of Ganja in 1804, many Ayrums and Qarapapaqs were resettled in Tabriz, Iran. Throughout the 1804–1813 war, and later during the 1826–1828 conflict, more of these groups from the newly conquered Russian territories migrated to Solduz in present-day West Azerbaijan province, Iran.^[58] The Russian military activities and governance issues in the Caucasus drove large numbers of Muslims and some Georgian Christians into exile in Iran.^[59]

From 1864 until the early 20th century, further expulsions and voluntary migrations occurred following the Russian victory in the Caucasian War. This led to additional movements of Caucasian Muslims, including Azerbaijani, other Transcaucasian Muslims, and North Caucasian groups like Circassians, Shia Lezgins, and Laks, towards Iran and Turkey.^[57] Many of these migrants played crucial roles in Iran's history, forming a significant part of the Persian Cossack Brigade established in the late 19th century.^[60]

The Treaty of Turkmenchay in 1828 also facilitated the resettlement of Armenians from Iran to the newly Russian-controlled territories.^[61] Historically, Armenians were a majority in Eastern Armenia but became a minority following Timur's campaigns and subsequent Islamic dominance.^[62] The Russian invasion of Iran further altered the ethnic composition, leading to an Armenian majority in Eastern Armenia by 1832. This demographic shift was further solidified after the Crimean War and the Russo-Turkish War of 1877–1878.^[63]

During this period, Iran experienced increased Western diplomatic engagement under Fath Ali Shah. His grandson, Mohammad Shah Qajar, influenced by Russia, unsuccessfully attempted to capture Herat. Naser al-Din Shah Qajar, succeeding Mohammad Shah, was a more successful ruler, founding Iran's first modern hospital.^[64]

The Great Persian Famine of 1870–1871 was a catastrophic event, resulting in the death of approximately two million people.^[65] This period marked a significant transition in Persian history, leading to the Persian Constitutional Revolution against the Shah in the late 19th and early 20th centuries. Despite challenges, the Shah conceded to a limited constitution in 1906, transforming Persia into a constitutional monarchy and leading to the convening of the first Majlis (parliament) on October 7, 1906.

The discovery of oil in 1908 in Khuzestan by the British intensified foreign interests in Persia, particularly by the British Empire (related to William Knox D'Arcy and the Anglo-Iranian Oil Company, now BP). This period was also marked by the geopolitical rivalry between the United Kingdom and Russia over Persia, known as The Great Game. The Anglo-Russian Convention of 1907 divided Persia into spheres of influence, undermining its national sovereignty.

During World War I, Persia was occupied by British, Ottoman, and Russian forces but remained largely neutral. Post-World War I and the Russian Revolution, Britain attempted to establish a protectorate over Persia, which ultimately failed.

The instability within Persia, highlighted by the Constitutionalist movement of Gilan and the Qajar government's weakening, paved the way for the rise of Reza Khan, later Reza Shah Pahlavi, and the establishment of the Pahlavi dynasty in 1925. A pivotal 1921 military coup, led by Reza Khan of the Persian Cossack Brigade and Seyyed Zia'eddin Tabatabai, was initially aimed at controlling government officials rather than directly overthrowing the Qajar monarchy.^[66] Reza Khan's influence grew, and by 1925, after serving as prime minister, he became the first Shah of the Pahlavi dynasty.

The 1921 Persian coup d'état, a pivotal event in Iran's history, unfolded in a context marked by political instability and foreign interventions. On February 21, 1921, Reza Khan, an officer in the Persian Cossack Brigade, and Seyyed Zia'eddin Tabatabaee, an influential journalist, orchestrated a coup that would profoundly alter the trajectory of the nation.

Iran, in the early 20th century, was a country in turmoil. The constitutional revolution of 1906-1911 had initiated a transition from an absolute monarchy to a constitutional one, but the country remained deeply fragmented with various factions vying for power. The Qajar dynasty, ruling since 1796, was weakened by internal strife and external pressures, particularly from Russia and Britain, which sought to exert influence over Iran's rich natural resources.

Reza Khan's rise to prominence began in this turbulent landscape. Born in 1878, he climbed the military ranks to become a brigadier general in the Persian Cossack Brigade, a well-trained and equipped military force originally formed by the Russians. Seyyed Zia, on the other hand, was a prominent journalist with a vision of a modernized Iran, free from foreign domination.

Their paths converged on that fateful day in February 1921. In the early hours, Reza Khan led his Cossack Brigade into Tehran, encountering minimal resistance. The coup was meticulously planned and executed with precision. By dawn, they had control of key government buildings and communication centers.

Ahmad Shah Qajar, the young and ineffectual monarch, found himself virtually powerless against the coup plotters. Seyyed Zia, with Reza Khan's backing, forced the Shah to appoint him as Prime Minister. This move was a clear indication of the power shift – from a weak monarchy to a new regime that promised reform and stability.

The immediate aftermath of the coup saw significant changes in Iran's political landscape. Seyyed Zia's tenure as Prime Minister, though brief, was marked by attempts at modernization and centralization. He sought to reform the administrative structure, curb corruption, and establish a modern legal system. However, his tenure was short-lived; he was forced to resign in June 1921, primarily due to opposition from traditional factions and his failure to consolidate power effectively.

Reza Khan, however, continued his ascendancy. He became the Minister of War and later the Prime Minister in 1923. His policies were geared towards strengthening the central government, modernizing the army, and reducing foreign influence. In 1925, he took a decisive step by deposing the Qajar dynasty and crowning himself as Reza Shah Pahlavi, founding the Pahlavi dynasty that would rule Iran until 1979.

The 1921 coup d'état marked a turning point in Iran's history. It set the stage for the rise of Reza Shah and the eventual establishment of the Pahlavi dynasty. The event symbolized the end of the Qajar era and the beginning of a period of significant transformation, as Iran embarked on a path towards modernization and centralization. The coup's legacy is complex, reflecting both the aspirations for a modern, independent Iran and the challenges of authoritarian rule that would characterize much of the 20th-century Iranian political landscape.

Reza Shah Pahlavi's rule from 1925 to 1941 in Iran was marked by significant modernization efforts and the establishment of an authoritarian regime. His government emphasized nationalism, militarism, secularism, and anti-communism, alongside strict censorship and propaganda.^[67] He introduced numerous socio-economic reforms, including reorganizing the army, government administration, and finances.^[68] Reza Shah's reign was a complex period of significant modernization and authoritarian rule, marked by both achievements in infrastructure and education and criticisms for oppression and political suppression.

To his supporters, Reza Shah's reign was seen as a period of significant progress, characterized by the introduction of law and order, discipline, central authority, and modern amenities like schools, trains, buses, radios, cinemas, and telephones.^[69] However, his rapid modernization efforts faced criticism for being "too fast"^[70] and "superficial,"^[71] with some viewing his reign as a time marked by oppression, corruption, excessive taxation, and a lack of authenticity. His rule was also likened to a police state due to its stringent security measures.^[69] His policies, especially those conflicting with Islamic traditions, caused discontent among devout Muslims and the clergy, leading to significant unrest, such as the 1935 rebellion at the Imam Reza shrine in Mashhad.^[72]

During Reza Shah's 16-year rule, Iran witnessed significant development and modernization. Major infrastructure projects were undertaken, including extensive road construction and the building of the Trans-Iranian Railway. The establishment of the University of Tehran marked the introduction of modern education in Iran.^[73] Industrial growth was substantial, with a 17-fold increase in the number of modern industrial plants, excluding oil installations. The country's highway network expanded from 2,000 to 14,000 miles.^[74]

Reza Shah dramatically reformed the military and civil services, founding a 100,000-man army,^[75] transitioning from reliance on tribal forces, and establishing a 90,000-man civil service. He set up free, compulsory education for both males and females and shut down private religious schools—Islamic, Christian, Jewish, etc.^[76] Additionally, he utilized funds from wealthy shrine endowments, notably in Mashhad and Qom, for secular purposes such as education, healthcare, and industrial projects.^[77]

Reza Shah's rule coincided with the Women's Awakening (1936–1941), a movement advocating for the removal of the chador in working society, arguing that it hindered women's physical activities and societal participation. This reform, however, faced resistance from religious leaders. The unveiling movement was closely linked to the Marriage Law of 1931 and the Second Congress of Eastern Women in Tehran in 1932.

In terms of religious tolerance, Reza Shah was notable for showing respect to the Jewish community, being the first Iranian monarch in 1400 years to pray in a synagogue during his visit to the Jewish community in Isfahan. This act significantly boosted the self-esteem of Iranian Jews and led to Reza Shah being highly regarded among them, second only to Cyrus the Great. His reforms allowed Jews to pursue new occupations and move out of ghettos.^[78] However, there were also claims of anti-Jewish incidents in Tehran in 1922 during his rule.^[79]

Historically, the term "Persia" and its derivatives were commonly used in the Western world to refer to Iran. In 1935, Reza Shah requested that foreign delegates and the League of Nations adopt "Iran" – the name used by its native people and meaning "Land of the Aryans" – in formal correspondence. This request led to the increased use of "Iran" in the Western world, altering the common terminology for the Iranian nationality from "Persian" to "Iranian." Later, in 1959, the government of Shah Mohammad Reza Pahlavi, Reza Shah Pahlavi's son and successor, declared that both "Persia" and "Iran" could officially be used interchangeably. Despite this, the use of "Iran" continued to be more prevalent in the West.

In foreign affairs, Reza Shah sought to diminish foreign influence in Iran. He made significant moves, such as canceling oil concessions with the British and seeking alliances with countries like Turkey. He balanced foreign influence, notably between Britain, the Soviet Union, and Germany.^[80] However, his foreign policy strategies collapsed with the onset of World War II, leading to the Anglo-Soviet invasion of Iran in 1941 and his subsequent forced abdication.^[81]

During World War II, as German armies achieved success against the Soviet Union, the Iranian government, anticipating a German victory, refused British and Soviet demands to expel German residents. This led to the Allied invasion of Iran in August 1941 under Operation Countenance, where they easily overpowered Iran's weak army. The primary objectives were to secure Iranian oil fields and establish the Persian Corridor, a supply route to the Soviet Union. Despite the invasion and occupation, Iran maintained an official stance of neutrality. Reza Shah was deposed during this occupation and replaced by his son, Mohammad Reza Pahlavi.^[82]

The Tehran Conference in 1943, attended by the Allied powers, resulted in the Tehran Declaration, assuring Iran's post-war independence and territorial integrity. However, post-war, Soviet troops stationed in northwestern Iran did not promptly withdraw. Instead, they supported revolts leading to the establishment of short-lived, pro-Soviet separatist states in Azerbaijan and Iranian Kurdistan - the Azerbaijan People's Government and the Republic of Kurdistan, respectively, in late 1945. The Soviet presence in Iran continued until May 1946, ending only after Iran promised oil concessions. However, the Soviet-backed republics were soon overthrown, and the oil concessions were subsequently revoked.^[83]

Mohammad Reza Pahlavi's reign as the Shah of Iran, spanning from 1941 to 1979, represents a significant and complex era in Iranian history, marked by rapid modernization, political upheaval, and social change. His reign can be divided into distinct phases, each characterized by various political, economic, and social dynamics.

The early years of Mohammad Reza Shah's rule were overshadowed by World War II and the subsequent occupation of Iran by Allied forces. During this period, Iran faced significant political turmoil, including the forced abdication of his father, Reza Shah, in 1941. This period was a time of uncertainty, with Iran grappling with foreign influence and internal instability.

In the post-war era, Mohammad Reza Shah embarked on an ambitious modernization program, heavily influenced by Western models. The 1950s and 1960s witnessed the implementation of the White Revolution, a series of reforms aimed at modernizing the country's economy and society. These reforms included land redistribution, women's suffrage, and the expansion of education and health services. However, these changes also led to unintended consequences, such as the displacement of rural populations and the rapid urbanization of cities like Tehran.

The Shah's rule was also marked by his increasingly autocratic style of governance. The 1953 coup, orchestrated with the assistance of the CIA and the British MI6, which reinstated him after a brief overthrow, significantly strengthened his position. This event was a turning point, leading to a more authoritarian regime, characterized by the suppression of political dissent and the marginalization of opposition parties. The SAVAK, the secret police established with the help of the CIA, became infamous for its brutal tactics in suppressing opposition.

Economically, Iran experienced significant growth during this period, largely fueled by its vast oil reserves. The 1970s saw a surge in oil revenues, which the Shah used to finance ambitious industrial projects and military expansions. However, this economic boom also led to increased inequality and corruption, contributing to societal discontent.

Culturally, the Shah's era was a time of significant transformation. The promotion of Western culture and values, alongside the suppression of traditional and religious practices, led to a cultural identity crisis among many Iranians. This period witnessed the rise of a Western-educated elite, often disconnected from the broader population's traditional values and lifestyles.

The late 1970s marked the decline of Mohammad Reza Shah's rule, culminating in the Islamic Revolution of 1979. The revolution, led by Ayatollah Ruhollah Khomeini, was a response to decades of autocratic rule, socio-economic inequality, and cultural Westernization. The Shah's inability to effectively respond to the growing unrest, exacerbated by his health issues, ultimately led to his overthrow and the establishment of the Islamic Republic of Iran.

The 1953 Iranian coup d'état was a significant political event where the democratically elected Prime Minister Mohammad Mosaddegh was overthrown. This coup, occurring on 19 August 1953,^[84] was orchestrated by the United States and the UK, and led by the Iranian army, to strengthen the monarchical rule of Shah Mohammad Reza Pahlavi. It involved U.S. involvement under the name Operation Ajax^[85] and the UK's Operation Boot.^[86] The Shi'a clergy also played a considerable role in this event.^[87]

The root of this political upheaval lay in Mosaddegh's attempts to audit the Anglo-Iranian Oil Company (AIOC, now BP) and limit its control over Iranian oil reserves. His government's decision to nationalize Iran's oil industry and expel foreign corporate representatives led to a global boycott of Iranian oil initiated by Britain,^[88] severely impacting Iran's economy. The UK, under Prime Minister Winston Churchill, and the U.S. Eisenhower administration, fearing Mosaddegh's unyielding stance and concerned about the Tudeh Party's communist influence, decided to overthrow Iran's government.^[89]

Post-coup, General Fazlollah Zahedi's government was established, allowing the Shah to rule with increased authority,^[90] heavily supported by the U.S..^[91] The CIA, as revealed by declassified documents, was deeply involved in the planning and execution of the coup, including hiring mobs to incite pro-Shah riots.^[84] The conflict resulted in 200 to 300 deaths, and Mosaddegh was arrested, tried for treason, and sentenced to house arrest for life.^[92]

The Shah continued his rule for another 26 years until the Iranian Revolution in 1979. In 2013, the U.S. government formally acknowledged its role in the coup with the release of classified documents, revealing the extent of its involvement and planning. In 2023, the CIA admitted that backing the coup was "undemocratic," highlighting the significant impact of this event on Iran's political history and U.S.-Iran relations.^[93]

The Iranian Revolution, culminating in 1979, marked a pivotal change in Iran's political landscape, leading to the overthrow of the Pahlavi dynasty and the establishment of the Islamic Republic of Iran. This transition ended the monarchical rule of Pahlavi and ushered in the theocratic government led by Ayatollah Ruhollah Khomeini.^[94] The ousting of Pahlavi, the last Shah of Iran, formally marked the end of Iran's historical monarchy.^[95]

Post-1953 coup, Pahlavi aligned Iran with the Western Bloc, particularly the United States, to strengthen his authoritarian rule. For 26 years, he maintained Iran's position away from Soviet influence.^[96] The Shah's modernization efforts, known as the White Revolution, began in 1963, which led to the exile of Khomeini, a vocal opponent of Pahlavi's policies. However, ideological tensions between Pahlavi and Khomeini persisted, leading to widespread anti-government demonstrations starting in October 1977.^[97]

The Cinema Rex fire in August 1978, where hundreds died, became a catalyst for a broader revolutionary movement.^[98] Pahlavi left Iran in January 1979, and Khomeini returned from exile in February, greeted by several thousands of supporters.^[99] By 11 February 1979, the monarchy collapsed, and Khomeini assumed control.^[100] Following the March 1979 Islamic Republic referendum, in which 98% of Iranian voters approved the country's shift to an Islamic republic, the new government began efforts to draft the present-day Constitution of the Islamic Republic of Iran;^[101] Ayatollah Khomeini emerged as the Supreme Leader of Iran in December 1979.^[102]

The success of the Iranian Revolution in 1979 was met with global surprise due to its unique characteristics. Unlike typical revolutions, it did not stem from defeat in war, a financial crisis, peasant uprisings, or military dissatisfaction. Instead, it occurred in a country experiencing relative prosperity and brought about rapid, profound changes. The revolution was massively popular and led to a significant exile, forming a large part of today's Iranian diaspora.^[103] It replaced Iran's pro-Western secular and authoritarian monarchy with an anti-Western Islamist theocracy. This new regime was based on the concept of Velâyat-e Faqih (Guardianship of the Islamic Jurist), a form of governance straddling authoritarianism and totalitarianism.^[104]

The revolution set forth a core ideological objective of destroying the Israeli state^[105] and sought to undermine Sunni influence in the region. It supported the political ascendancy of Shi'ites and exported Khomeinist doctrines internationally.Following the consolidation of Khomeinist factions, Iran began to back Shia militancy across the region to combat Sunni influence and establish Iranian dominance, aiming for an Iranian-led Shia political order.

Ayatollah Ruhollah Khomeini was the preeminent figure in Iran from the establishment of the Islamic Republic in April 1979 until his death in 1989. The Islamic Revolution significantly impacted global perceptions of Islam, sparking interest in Islamic politics and spirituality, but also generating fear and distrust towards Islam and particularly the Islamic Republic and its founder.^[106]

The revolution inspired Islamist movements and opposition to Western influence in the Muslim world. Notable events include the takeover of the Grand Mosque in Saudi Arabia in 1979, the assassination of Egyptian President Sadat in 1981, the Muslim Brotherhood rebellion in Hama, Syria, and the 1983 bombings in Lebanon targeting American and French forces.^[107]

Between 1982 and 1983, Iran addressed the aftermath of the revolution, including economic, military, and governmental rebuilding. During this period, the regime suppressed uprisings by various groups who were once allies but had become political rivals. This led to the execution of many political opponents. Revolts in Khuzistan, Kurdistan, and Gonbad-e Qabus by Marxists and federalists resulted in intense conflict, with the Kurdish uprising being particularly prolonged and deadly.

The Iran hostage crisis, beginning in November 1979 with the seizure of the U.S. embassy in Tehran, significantly influenced the revolution. The crisis led to severed U.S.-Iran diplomatic relations, economic sanctions by the Carter administration, and a failed rescue attempt that bolstered Khomeini's stature in Iran. The hostages were eventually released in January 1981 following the Algiers Accords.^[108]

Internal disagreements about the future of Iran surfaced post-revolution. While some anticipated a democratic government, Khomeini opposed this notion, stating in March 1979, "do not use this term, ‘democratic.’ That is the Western style".^[109] Various political groups and parties, including the National Democratic Front, the provisional government, and the People's Mujahedin of Iran, faced bans, attacks, and purges.^[110]

In 1979, a new constitution was drafted, establishing Khomeini as the Supreme Leader with substantial powers and instituting a clerical Council of Guardians with oversight of legislation and elections. This constitution was ratified via a referendum in December 1979.^[111]

The Iran-Iraq War, lasting from September 1980 to August 1988, was a significant conflict between Iran and Iraq. It began with an Iraqi invasion and continued for eight years, ending with the acceptance of UN Security Council Resolution 598 by both parties. Iraq, led by Saddam Hussein, invaded Iran primarily to prevent Ayatollah Ruhollah Khomeini from exporting Iran's revolutionary ideology to Iraq. There were also Iraqi concerns about Iran's potential to incite Iraq's Shia majority against its Sunni-dominated, secular Ba'athist government. Iraq aimed to assert itself as the dominant power in the Persian Gulf, a goal that seemed more attainable after Iran's Islamic Revolution weakened its previously strong ties with the United States and Israel.

During the political and social turmoil of the Iranian Revolution, Saddam Hussein saw an opportunity to capitalize on the disarray. The Iranian military, once robust, had been significantly weakened by the revolution. With the Shah deposed and Iran's relations with Western governments strained, Saddam aimed to assert Iraq as a dominant force in the Middle East.Saddam's ambitions included expanding Iraq's access to the Persian Gulf and reclaiming territories previously contested with Iran during the Shah's regime. A key target was Khuzestan, an area with a substantial Arab population and rich oil fields. Additionally, Iraq had interests in the islands of Abu Musa and the Greater and Lesser Tunbs, which were strategically important and claimed unilaterally on behalf of the United Arab Emirates. The war was also fueled by longstanding territorial disputes, notably over the Shatt al-Arab waterway. Post-1979, Iraq increased support for Arab separatists in Iran and aimed to regain control of the Shatt al-Arab's eastern bank, which it had conceded to Iran in the 1975 Algiers Agreement.

Confident in his military's capabilities, Saddam planned an extensive assault on Iran, claiming that Iraqi forces could reach Tehran within three days. On September 22, 1980, this plan was set into motion when the Iraqi army invaded Iran, targeting the region of Khuzestan. This invasion marked the beginning of the Iran-Iraq War and caught the revolutionary Iranian government off guard. Contrary to Iraqi expectations of a quick victory exploiting post-revolutionary chaos in Iran, the Iraqi military advance stalled by December 1980. Iran regained almost all its lost territory by June 1982. Rejecting a UN ceasefire, Iran invaded Iraq, leading to five years of Iranian offensives. By mid-1988, Iraq launched major counter-offensives, resulting in a stalemate.

The war caused immense suffering, with approximately 500,000 deaths, excluding civilian casualties in the Anfal campaign against Iraqi Kurds. It ended without reparations or border changes, with both nations incurring over US$1 trillion in financial losses.^[112] Both sides used proxy forces: Iraq was supported by the National Council of Resistance of Iran and various Arab militias, while Iran allied with Iraqi Kurdish groups. International support varied, with Iraq receiving aid from Western and Soviet bloc countries and most Arab nations, while Iran, more isolated, was supported by Syria, Libya, China, North Korea, Israel, Pakistan, and South Yemen.

The war's tactics resembled World War I, including trench warfare, use of chemical weapons by Iraq, and deliberate attacks on civilians. A notable aspect of the war was Iran's state-sanctioned promotion of martyrdom, leading to the widespread use of human wave attacks, significantly influencing the conflict's dynamics.^[113]

Akbar Hashemi Rafsanjani's presidency, which began on August 16, 1989, was marked by a focus on economic liberalization and a push towards privatization, contrasting with the more state-controlled approach of previous administrations in the Islamic Republic of Iran. Described as "economically liberal, politically authoritarian, and philosophically traditional," Rafsanjani's administration faced opposition from radical elements within the Majles (Iranian parliament).^[114]

During his tenure, Rafsanjani was instrumental in Iran's post-war reconstruction following the Iran-Iraq War.^[115] His administration attempted to curb the powers of ultra-conservatives, but these efforts were largely unsuccessful as the Iranian Revolutionary Guards gained more power under the guidance of Khamenei. Rafsanjani faced allegations of corruption from both conservative^[116] and reformist factions,^[117] and his presidency was known for harsh crackdowns on dissent.^[118]

Post-war, Rafsanjani's government focused on national development. The first development plan of the Islamic Republic of Iran was drafted under his administration, aiming to modernize Iran's defense, infrastructure, culture, and economy. The plan sought to meet basic needs, reform consumption patterns, and improve administrative and judicial management. Rafsanjani's government was noted for prioritizing industrial and transportation infrastructure development.

Domestically, Rafsanjani championed a free market economy, pursuing economic liberalization with state coffers bolstered by oil revenues. He aimed to integrate Iran into the global economy, advocating for structural adjustment policies inspired by the World Bank. This approach sought a modern industrial-based economy, contrasting with the policies of his successor, Mahmoud Ahmadinejad, who favored economic redistribution and a hardline stance against Western intervention. Rafsanjani encouraged collaboration between universities and industries, emphasizing the need to adapt to the rapidly changing global landscape. He initiated projects like the Islamic Azad University, signaling a commitment to education and development.^[119]

Rafsanjani's tenure also saw the execution of various groups by Iran's judicial system, including political dissidents, Communists, Kurds, Baháʼís, and even some Islamic clerics. He took a particularly hard stance against the People's Mojahedin Organization of Iran, advocating harsh punishments in line with Islamic law.^[120] Rafsanjani worked closely with Khamenei to ensure governmental stability following Khomeini's death.

In foreign affairs, Rafsanjani worked to mend relations with Arab states and expand ties with countries in Central Asia and the Caucasus. However, relationships with Western nations, particularly the U.S., remained strained. Rafsanjani's government provided humanitarian aid during the Persian Gulf War and voiced support for peace initiatives in the Middle East. He also played a significant role in supporting Iran's nuclear program, assuring that Iran's use of nuclear technology was peaceful.^[121]

The eight years of Mohammad Khatami's two terms as president in 1997–2005 are sometimes called Iran's Reform Era.^[122] Mohammad Khatami's presidency, beginning on May 23, 1997, marked a significant shift in Iran's political landscape, emphasizing reform and modernization. Winning the election with a remarkable 70% of the vote amid a high turnout of nearly 80%, Khatami's victory was notable for its broad-based support, including traditional leftists, business leaders advocating economic openness, and younger voters.^[123]

Khatami's election signaled a desire for change in Iranian society, particularly after the Iran-Iraq War and the post-conflict reconstruction period. His presidency, often associated with the "2nd of Khordad Movement," focused on the rule of law, democracy, and inclusive political participation. At first, the new era saw significant liberalization. The number of daily newspapers published in Iran increased from five to twenty-six. Journal and book publishing also soared. Iran's film industry boomed under the Khatami regime and Iranian films won prizes at Cannes, and Venice.^[124] However, his reformist agenda frequently clashed with Iran's conservative elements, particularly those in powerful positions like the Guardian Council. These clashes often resulted in Khatami's defeat in political battles, leading to disillusionment among his supporters. In 1999, new curbs were put on the press. Courts banned more than 60 newspapers.^[124] Important allies of President Khatami were arrested, tried and imprisoned on what outside observers considered "trumped up"^[125] or ideological grounds.

Khatami's administration was constitutionally subordinate to the Supreme Leader, limiting his authority over key state institutions. His notable legislative attempt, the "twin bills," aimed to reform election laws and clarify presidential powers. These bills were passed by the parliament but were vetoed by the Guardian Council, symbolizing the challenges Khatami faced in implementing reforms.

Khatami's presidency was characterized by an emphasis on press freedom, civil society, women's rights, religious tolerance, and political development. He sought to improve Iran's image internationally, engaging with the European Union and becoming the first Iranian president to visit several European countries. His economic policies continued the industrialization efforts of previous governments, focusing on privatization and integrating Iran's economy into the global market. Despite these efforts, Iran faced significant challenges, including unemployment and a persistent struggle with poverty.

In foreign policy, Khatami aimed for conciliation over confrontation, advocating a "Dialogue Among Civilizations" and attempting to mend relations with the West. Several European Union countries began renewing economic ties with Iran in the late 1990s, and trade and investment increased. In 1998, Britain re-established diplomatic relations with Iran, broken since the 1979 revolution. The United States loosened its economic embargo, but it continued to block more normalized relations, arguing that the country had been implicated in international terrorism and was developing a nuclear weapons capacity.

Mahmoud Ahmadinejad, elected as Iran's president in 2005 and re-elected in 2009, was known for his conservative populist stance. He promised to combat corruption, advocate for the poor, and strengthen national security. In the 2005 election, he defeated former President Rafsanjani significantly, attributed to his economic promises and lower reformist voter turnout. This victory consolidated conservative control over the Iranian government.^[126]

Ahmadinejad's presidency was marked by controversy, including his vocal opposition to American policies and his contentious remarks about Israel.^[127] His economic policies, such as providing cheap loans and subsidies, were blamed for high unemployment and inflation.^[128] His 2009 re-election faced significant dispute, sparking large protests described as the greatest domestic challenge to Iran's leadership in three decades.^[129] Despite allegations of voting irregularities and ongoing protests, Supreme Leader Ali Khamenei endorsed Ahmadinejad's victory,^[130] while foreign powers were blamed for inciting unrest.^[131]

A rift between Ahmadinejad and Khamenei emerged, centered around Ahmadinejad's advisor, Esfandiar Rahim Mashaei, accused of leading a "deviant current" against greater clerical involvement in politics.^[132] Ahmadinejad's foreign policy maintained strong ties with Syria and Hezbollah and developed new relationships with Iraq and Venezuela. His direct communications with world leaders, including a letter to George W. Bush and remarks about the absence of homosexuals in Iran, garnered significant attention.

Under Ahmadinejad, Iran's nuclear program led to international scrutiny and accusations of non-compliance with the Nuclear Nonproliferation Treaty. Despite Iran's insistence on peaceful intentions, the IAEA and international community expressed concerns, and Iran agreed to tougher inspections in 2013.^[133] During his tenure, several Iranian nuclear scientists were assassinated.^[134]

Economically, Ahmadinejad's policies were initially supported by high oil revenues, which declined with the 2008 financial crisis.^[128] In 2006, Iranian economists criticized his economic interventions, and his decision to dissolve the Management and Planning Organisation of Iran in 2007 was seen as a move to implement more populist policies.

Human rights under Ahmadinejad reportedly deteriorated, with increased executions and crackdowns on civil liberties, including dress codes and restrictions on dog ownership.^[135] Controversial proposals, such as promoting polygamy and taxing Mahriyeh, did not materialize.^[136] The 2009 election protests led to widespread arrests and deaths, but a September 2009 poll suggested high levels of satisfaction with the regime among Iranians.^[137]

Hassan Rouhani, elected as Iran's president in 2013 and re-elected in 2017, focused on recalibrating Iran's global relations. He aimed for greater openness and international trust,^[138] particularly regarding Iran's nuclear program. Despite criticism from conservative factions like the Revolutionary Guards, Rouhani pursued policies of dialogue and engagement. Rouhani's public image varied, with high approval ratings post-nuclear deal, but challenges in maintaining support due to economic expectations.

Rouhani's economic policy centered on long-term development, focusing on increasing public purchasing power, controlling inflation, and reducing unemployment.^[139] He planned to regenerate the Management and Planning Organization of Iran and control inflation and liquidity.

In terms of culture and media, Rouhani faced criticism for not having complete control over internet censorship. He advocated for greater freedom in private lives and access to information.^[140] Rouhani supported women's rights, appointing women and minorities to high positions, but faced skepticism about creating a ministry for women.^[141]

Human rights under Rouhani were a contentious issue, with criticisms of the high number of executions and limited progress in addressing systemic issues. However, he made symbolic gestures, like freeing political prisoners and appointing a diverse range of ambassadors.^[142]

In foreign policy, Rouhani's tenure was marked by efforts to repair ties with neighboring countries^[143] and engage in nuclear negotiations. His administration worked on improving relations with the UK^[144] and cautiously navigated complex relations with the United States. Rouhani continued Iran's support for Bashar al-Assad in Syria and engaged in regional dynamics, especially with Iraq, Saudi Arabia, and Israel.^[145]

Ebrahim Raisi became Iran's president on 3 August 2021, with a focus on addressing sanctions and promoting economic independence from foreign influence. He was officially sworn in before the Islamic Consultative Assembly on 5 August, emphasizing Iran's role in stabilizing the Middle East, resisting foreign pressure, and assuring the peaceful nature of Iran's nuclear program.

Raisi's tenure saw a surge in COVID-19 vaccine imports and a pre-recorded speech at the United Nations General Assembly, emphasizing Iran's willingness to resume nuclear talks. However, his presidency faced challenges with the eruption of protests following Mahsa Amini's death and accusations of human rights violations.

In foreign policy, Raisi expressed support for an inclusive Afghan government post-Taliban takeover and criticized Israel, calling it a "false regime". Under Raisi, Iran continued negotiations over the JCPOA, though progress remained stalled.

Raisi is considered a hardliner, advocating for sex segregation, Islamization of universities, and censorship of Western culture. He views economic sanctions as an opportunity for Iran's self-reliance and supports agricultural development over commercial retail. Raisi emphasizes cultural development, women's rights, and the role of intellectuals in society. His economic and cultural policies reflect a focus on national self-sufficiency and traditional values.