The history of Iran

Iran occupies a high plateau ringed by mountains between the Caspian Sea and the Persian Gulf, and it has been home to some of the oldest states on earth. Elam flourished in the southwest from the third millennium BCE, and in the sixth century BCE Cyrus the Great built the Achaemenid Empire, the largest the world had yet seen. Persian kingdoms under the Parthians and Sasanians rivalled Rome for centuries, and after the Arab conquest of the seventh century Iran became Muslim while keeping its language and much of its culture, which went on to shape the whole eastern Islamic world. The Safavids made Iran a Shia state in 1501, the Qajars lost territory to Russia and Britain's influence, and the Pahlavi shahs pushed a rapid, authoritarian modernisation that ended in the revolution of 1979. Since then the Islamic Republic has fought a long war with Iraq, faced decades of sanctions over its nuclear programme, and in 2025 and 2026 came under direct attack from Israel and the United States.

Stone tools show that early humans lived on the Iranian plateau more than 100,000 years ago, and Neanderthal remains have been found in caves of the Zagros Mountains. The western Zagros formed part of the arc where the Neolithic Revolution took place: at sites such as Chogha Golan, people were cultivating wild barley and wheat in the eleventh and tenth millennia BCE, and goats were domesticated in the region around the same time. Villages of mud-brick houses spread across the plateau, and by the fifth millennium BCE painted pottery of great refinement was being made at sites like Tepe Sialk near Kashan.

Susa, in the lowland plain of Khuzestan that continues the flatlands of Mesopotamia, was settled by the late fifth millennium BCE. Further east, the Jiroft culture of Kerman produced carved chlorite vessels in the third millennium BCE, and the city of Shahr-e Sukhteh in Sistan traded with the Indus Valley civilisation and with Sumer. Iran's tin, copper, lapis lazuli and carnelian already moved along overland routes that would one day form part of the Silk Road.

Elam, centred on Susa and Anshan in the southwest, was the first great state of Iran. Its scribes developed a Proto-Elamite script around 3200 BCE, and for more than two thousand years its kings fought, traded and intermarried with the city-states and empires of Mesopotamia. Elamite armies sacked Ur around 2004 BCE, and in the twelfth century BCE King Shutruk-Nakhunte carried off the law code of Hammurabi from Babylon to Susa, where archaeologists found it in 1901. The ziggurat of Chogha Zanbil, built around 1250 BCE, is the best-preserved of its kind. Elam's long rivalry with Assyria ended in disaster in 646 BCE, when Ashurbanipal sacked Susa.

By then Iranian-speaking peoples, who had migrated onto the plateau from Central Asia during the second and early first millennia BCE, were the dominant population. The Persians settled in the old Elamite highlands of Fars, while the Medes formed a kingdom in the northwest with its capital at Ecbatana, modern Hamadan. In 612 BCE the Median king Cyaxares, allied with Babylonia, destroyed the Assyrian capital Nineveh. The religious reformer Zoroaster, whose dates remain uncertain, probably lived somewhere in eastern Iran or Central Asia, and the faith that bears his name, Zoroastrianism, with its struggle between truth and the lie, became the religion of the Iranian kings.

Around 550 BCE Cyrus the Great, a Persian king who had been a vassal of the Medes, overthrew his overlord and took the Median realm. He went on to conquer Lydia in Anatolia and, in 539 BCE, Babylon itself, where he allowed deported peoples, among them the Jews, to return home. His son Cambyses II added Egypt. The Achaemenid Empire eventually stretched from the Aegean and Egypt to the Indus, ruling perhaps a third or more of the world's population.

Darius the Great, who seized the throne in 522 BCE, gave the empire its lasting structure. He divided it into provinces called satrapies, set fixed tribute, introduced a gold coin, the daric, built the Royal Road from Susa to Sardis with its relay stations, and began the ceremonial capital of Persepolis. His inscription at Behistun, carved in Old Persian, Elamite and Babylonian, later allowed scholars to decipher cuneiform. The empire was notably tolerant of local religions and customs and used Aramaic as a common administrative language.

A revolt of the Ionian Greek cities in 499 BCE, aided by Athens, led to the Greco-Persian Wars. Darius's expedition was defeated at the Battle of Marathon in 490 BCE, and the far larger invasion of Xerxes I in 480 BCE burned Athens but was turned back at Salamis and Plataea. The Greek historian Herodotus wrote his account of these wars a generation later. Persia nevertheless remained the dominant power of the region for another 150 years, until Alexander the Great invaded in 334 BCE, defeated Darius III at Issus and Gaugamela, and burned Persepolis in 330 BCE.

After Alexander's death most of Iran passed to his general Seleucus, whose Seleucid Empire planted Greek settlers and cities across the east. Its hold on the plateau was weak, and from about 247 BCE the Parni, a nomadic people from the steppe east of the Caspian, founded the Arsacid kingdom of Parthia. Under Mithridates I in the mid-second century BCE the Parthian Empire took Media and Mesopotamia, building its winter capital at Ctesiphon on the Tigris.

Parthia was a loose, feudal realm whose great noble families commanded the armoured cavalry and horse archers that made it a formidable opponent. In 53 BCE the Parthian general Surena destroyed the army of Crassus at Carrhae, and for nearly three centuries Parthia and the Roman Empire contended for Armenia and Mesopotamia. Parthia controlled the overland trade between Rome and Han China, and its kings, though they adopted Greek styles at first, increasingly presented themselves as heirs of the old Iranian monarchy.

In 224 CE Ardashir I, a ruler from Fars, defeated and killed the last Parthian king, Artabanus IV, and founded the Sasanian Empire. The Sasanians ruled a more centralised state than their predecessors and made Zoroastrianism an official religion with a powerful priesthood. Ardashir's son Shapur I defeated three Roman emperors and in 260 captured the emperor Valerian, an event he commemorated in rock reliefs near Persepolis. In the third century the prophet Mani founded Manichaeism in the empire, a faith that spread from North Africa to China before it was suppressed.

The empire reached a high point under Khosrow I (531 to 579), who reformed taxation and the army, welcomed Greek philosophers expelled from Athens, and fought Justinian I and the Byzantine Empire. Khosrow II overran Syria, Jerusalem and Egypt after 602, but the Byzantine emperor Heraclius counter-attacked deep into Mesopotamia, and the long war of 602 to 628 left both empires exhausted. Sasanian court culture, its silverwork, its music and its ideas of kingship, deeply influenced the later Islamic world.

Within a few years of the death of the Prophet Muhammad, Arab armies of the Rashidun Caliphate defeated the Sasanians at al-Qadisiyyah in about 636 and at Nahavand in 642. The last shah, Yazdegerd III, was murdered near Merv in 651, and Iran became part of the caliphate, later ruled by the Umayyad Caliphate from Damascus. Conversion to Islam was gradual and took several centuries, and Zoroastrian communities survived, though steadily reduced; some migrated to India, where they became the Parsis.

Iranians were central to the revolution that brought the Abbasid Caliphate to power in 750, a movement launched in Khorasan by Abu Muslim. The Abbasids founded their capital at Baghdad, close to the old Sasanian capital, and modelled their court and bureaucracy on Persian practice. Iranians such as the mathematician Al-Khwarizmi, born in Khwarazm, and later the physician al-Razi of Rayy were leading figures of the Islamic Golden Age.

As Abbasid power weakened from the ninth century, local Iranian dynasties took over. The Tahirids and Saffarids ruled in the east, and the Samanid Empire, based in Bukhara, sponsored the revival of Persian as a written language in Arabic script; the poet Rudaki worked at its court. The Shia Buyid dynasty took Baghdad in 945 and controlled the caliphs themselves. The philosopher and physician Avicenna served several of these courts, and around 1010 the poet Ferdowsi completed the Shahnameh, the national epic of Iran, at the time of the Turkic Ghaznavid Empire.

In the eleventh century Turkic Oghuz tribes led by the Seljuk family swept into Iran, defeated the Ghaznavids at Dandanaqan in 1040, and in 1055 entered Baghdad. The Seljuk Empire was run largely by Persian administrators, above all the vizier Nizam al-Mulk, who founded colleges in its cities; the theologian Al-Ghazali taught in one of them, and the mathematician and poet Omar Khayyam worked on a reformed calendar for the sultan Malik Shah. Persian became the language of government and literature across a Turkic-ruled world.

The Mongol invasion that began in 1219 under Genghis Khan was among the most destructive events in Iranian history. Cities such as Nishapur, Merv and Herat were sacked and much of their population killed, and irrigation systems in the east were ruined. Genghis's grandson Hulagu destroyed the strongholds of the Nizari Ismailis and in 1258 sacked Baghdad, ending the Abbasid caliphate. He founded the Ilkhanate, a branch of the Mongol Empire ruled from Tabriz and Maragheh. Under Ghazan, who converted to Islam in 1295, and his vizier Rashid al-Din, author of a universal history, the Ilkhanate became a centre of learning and art, but it broke apart after 1335.

Tamerlane invaded from 1381, building towers of skulls at Isfahan and elsewhere, and his heirs in the Timurid Empire ruled eastern Iran from Herat, where Persian painting, poetry and architecture flourished in the fifteenth century. The poet Hafez of Shiraz had lived through the turmoil of the fourteenth century. In the west, Turkmen confederations ruled, first the Qara Qoyunlu and then the Aq Qoyunlu under Uzun Hasan.

In 1501 Ismail, the young head of the Safavid Sufi order, whose Turkmen followers were known as the Qizilbash, took Tabriz and proclaimed himself shah. He declared Twelver Shia Islam the state religion and imposed it, often by force, on a population that was mostly Sunni, a transformation that gave Iran its lasting religious identity and set it apart from its Sunni neighbours. The Safavid Empire fought the Ottoman Empire for more than a century; the Ottomans defeated Ismail at Chaldiran in 1514 and repeatedly took Tabriz and Baghdad.

Shah Abbas I (1588 to 1629) rebuilt the state. He created a standing army of slave soldiers drawn largely from Georgians, Armenians and Circassians, recovered lost territory from the Ottomans, expelled the Portuguese from Hormuz in 1622 with English help, and moved the capital to Isfahan, which he rebuilt around the vast Naqsh-e Jahan square, its mosques and palaces. He resettled thousands of Armenian merchants in New Julfa to run the silk trade. The empire later declined, and in 1722 an Afghan army under Mahmud Hotak besieged and took Isfahan, effectively ending Safavid rule.

A Turkmen commander, Nader, expelled the Afghans and pushed back Ottoman and Russian invaders, then had himself crowned shah in 1736. In 1739 he invaded the Mughal Empire, sacked Delhi and carried off the Peacock Throne, but his rule grew increasingly brutal and he was assassinated in 1747. Karim Khan Zand then ruled most of Iran from Shiraz, with a relatively mild government, until his death in 1779.

The Qajars, a Turkmen tribe, won the ensuing struggle; Agha Mohammad Khan made Tehran his capital and was crowned in 1796. The nineteenth century brought defeat by the Russian Empire, and the treaties of Gulistan in 1813 and Turkmenchay in 1828 surrendered the lands that are now Georgia, Armenia and Azerbaijan. Britain, guarding the approaches to India, forced Iran to give up its claim to Herat in Afghanistan in 1857. Iran was never colonised, but the two powers competed for influence and concessions, while a great famine in 1870 to 1872 killed a large part of the population.

Resistance to foreign concessions grew. In 1891 and 1892 a boycott led by the clergy forced the shah to cancel a tobacco monopoly granted to a British subject. The Constitutional Revolution of 1905 to 1911, backed by merchants, clerics and reformers, won a constitution and an elected parliament, the Majlis, which first met in October 1906. In 1907 Britain and Russia divided the country into spheres of influence, and Russian troops helped crush the constitutionalists in 1911. Oil was discovered in Khuzestan in 1908, and the Anglo-Persian Oil Company, later controlled by the British government, became a major force in Iranian life.

During World War I Iran was neutral but occupied by Ottoman, Russian and British forces, and famine struck again. In 1921 the Cossack officer Reza Khan seized power in a coup, and in 1925 he deposed the last Qajar and was proclaimed shah, founding the Pahlavi dynasty. Reza Shah built a national army, railways, modern schools and the University of Tehran, imposed Western dress, banned the women's veil in 1936 and crushed tribal and clerical opposition. In 1935 he asked foreign governments to call the country Iran instead of Persia. In August 1941, during World War II, British and Soviet forces invaded to secure a supply route to the Soviet Union, and Reza Shah abdicated in favour of his son, Mohammad Reza.

The early Cold War began partly in Iran, when Soviet troops were slow to leave in 1946 and backed separatist governments in Iranian Azerbaijan and Kurdistan. In 1951 the nationalist prime minister Mohammad Mosaddegh nationalised the oil industry, triggering a British boycott. In August 1953 he was overthrown in a coup organised by the CIA and British intelligence together with royalist officers, an event that shaped Iranian views of the West for decades.

Mohammad Reza Shah then ruled as an increasingly autocratic monarch allied with the United States. His White Revolution, launched in the early 1960s, brought land reform, votes for women and literacy campaigns, and oil wealth produced rapid growth after 1973. But the SAVAK secret police suppressed dissent, inequality and corruption grew, and the cleric Ruhollah Khomeini, exiled in 1964 after leading protests, became the focus of opposition from abroad.

Mass protests and strikes in 1978 brought together religious conservatives, liberals and the left. The shah left Iran in January 1979, and Khomeini returned to Tehran on 1 February to a huge welcome. After a referendum, Iran was proclaimed an Islamic Republic on 1 April 1979. Its constitution combined elected institutions, including a president and parliament, with the supreme authority of a senior jurist, a position Khomeini held. Over the next few years rival groups were eliminated, thousands of opponents were executed, and Islamic rules on dress and morality were imposed.

On 4 November 1979 students seized the American embassy in Tehran, holding 52 Americans hostage for 444 days and leading to a lasting break in relations with the United States. On 22 September 1980 Iraq under Saddam Hussein invaded, hoping to exploit the chaos. The Iran–Iraq War lasted eight years, with trench warfare, missile attacks on cities and Iraqi use of chemical weapons; estimates of the dead on both sides run to around half a million or more. A UN-brokered ceasefire took effect in August 1988. In the summer of 1988 the authorities also carried out mass executions of political prisoners, whose number is estimated at several thousand.

Khomeini died on 3 June 1989 and was succeeded as supreme leader by Ali Khamenei. Presidents Akbar Hashemi Rafsanjani and the reformist Mohammad Khatami presided over reconstruction and a limited opening, but conservative institutions such as the Guardian Council and the Islamic Revolutionary Guard Corps blocked deeper change. The disputed re-election of Mahmoud Ahmadinejad in 2009 provoked the mass protests of the Green Movement, which were suppressed.

Iran's nuclear programme, which Western governments and Israel suspected was aimed at weapons and which Iran said was peaceful, led to heavy international sanctions. In July 2015, under President Hassan Rouhani, Iran agreed the Joint Comprehensive Plan of Action with the United States, Russia, China, Britain, France and Germany, limiting its programme in exchange for sanctions relief. The United States withdrew in May 2018 and reimposed sanctions, and Iran later expanded its enrichment. Iran also built a network of allied armed groups in Lebanon, Syria, Iraq and Yemen, and in January 2020 a US drone strike in Baghdad killed the Revolutionary Guard commander Qasem Soleimani.

The death of 22-year-old Mahsa Amini in the custody of the morality police in September 2022 set off nationwide protests under the slogan "Woman, Life, Freedom", which were put down with many deaths. President Ebrahim Raisi, elected in 2021, was killed in a helicopter crash on 19 May 2024, and the reformist Masoud Pezeshkian won the presidency in July 2024.

On 13 June 2025 Israel launched air strikes on Iranian nuclear and military sites and senior commanders, and Iran answered with missile barrages on Israel. On 22 June the United States bombed the nuclear facilities at Fordow, Natanz and Isfahan, and a ceasefire took effect on 24 June, ending what became known as the Twelve-Day War. Iranian figures put the country's dead at more than a thousand. In September 2025 United Nations sanctions were reimposed through the "snapback" mechanism of the 2015 deal.

With the currency collapsing and inflation above 40 percent, protests began in Tehran's bazaar on 28 December 2025 and spread nationwide. In January 2026 security forces opened fire on demonstrators while the internet was cut. The government acknowledged more than 3,000 deaths; human rights groups documented several thousand more, and some estimates are far higher.

On 28 February 2026 the United States and Israel began a large-scale air war against Iran, and strikes on Tehran killed Ali Khamenei, supreme leader for 37 years. On 8 March the Assembly of Experts named his son, Mojtaba Khamenei, as the third supreme leader of the Islamic Republic. Iran fired missiles and drones at Israel, at US bases and at Gulf states, and closed the Strait of Hormuz, through which a large share of the world's oil passes; the United States responded with a naval blockade of Iranian ports. A memorandum signed in June to end the fighting broke down within weeks over control of the strait. As of October 2026 the two sides remained in an armed standoff, with Iranian attacks on shipping, a continuing US blockade, and indirect talks through Pakistan and Qatar that had not produced a settlement.