The oldest archaeological artifacts discovered in Iran, such as those discovered at the Kashafrud and Ganj Parsites, testify to a human presence in Iran dating back to the Lower Paleolithic period, about 800,000–200,000 BC. Neanderthal artifacts from the Middle Paleolithic era (c. 200,000–40,000 BC) in Iran have mostly been discovered in the Zagros area, at sites such as Warwasi and Yafteh Cave. Early agricultural towns such as Chogha Golan and Chogha Bonut started to thrive in Iran during the 10th to 8th millennia BC, with Susa and Chogha Mish emerging in and around the Zagros area.
According to radiocarbon dating, Susa first appeared as a city in early 4,395 BC. Hundreds of archaeological monuments dot the Iranian plateau, indicating the presence of ancient civilizations and urban populations in the fourth millennium BC. Several civilizations flourished in Iran throughout the Bronze Age, including Elam, Jiroft, and the Zayande River. Elam, the most notable of these civilizations, arose in southwest Iran alongside that of Mesopotamia. The development of writing in Elam mirrored that of Sumer, and the Elamite cuneiform was created as early as the third millennium BC.
The Elamite Kingdom survived until the rise of the Median and Achaemenid dynasties. Between 3400 BC to about 2000 BC, northern Iran was a member of the Kura-Araxes civilization, which spanned the Caucasus and Anatolia. Since the early second millennium BC, Assyrians have inhabited and absorbed large areas of western Iran into their domains.
Proto-Iraniantribes came in Iran from the Eurasian steppes around the second millennium BC, competing with the country’s original inhabitants. As these tribes spread across Greater Iran and beyond, the Persian, Median, and Parthian tribes controlled the borders of current Iran.
The Iranian peoples, along with the pre-Iranian kingdoms, were subject to the Assyrian Empire, which was located in northern Mesopotamia, from the late 10th to late 7th century BC. The Medes and Persians formed an alliance with Nabopolassar of Babylon, as well as the Scythians and Cimmerians, and invaded the Assyrian Empire under King Cyaxares. Between 616 BC to 605 BC, the Assyrian Empire was devastated by civil conflict, liberating their separate peoples from three centuries of Assyrian domination. The union of the Median tribes under a single king in 728 BC resulted in the establishment of the Median Empire, which ruled all of Iran and eastern Anatolia by 612 BC. This also signaled the end of the Kingdom of Urartu, which was afterwards invaded and destroyed.
Cyrus the Great, son of Mandane and Cambyses I, conquered the Median Empire in 550 BC and established the Achaemenid Empire by uniting other city states. The capture of Media was the outcome of the Persian Revolt. The uproar was sparked by the acts of Median king Astyages, and it soon extended to neighboring regions that cooperated with the Persians. Later conquests by Cyrus and his successors included Lydia, Babylon, Egypt, portions of the Balkans and Eastern Europe proper, as well as the territories west of the Indus and Oxus rivers.
The year 539 BC marked the end of approximately four centuries of Mesopotamian dominance of the area with the shift from the Neo-Babylonian Period to the Achaemenid Period, when Persian troops destroyed the Babylonian army at Opis. Cyrus arrived at Babylon and pretended to be a typical Mesopotamian king. The impact of the new political realities in Mesopotamia is reflected in subsequent Achaemenid art and iconography.
At its peak, the Achaemenid Empire encompassed modern-day Iran, Azerbaijan, Armenia, Georgia, Turkey, much of the Black Sea coastal regions, northeastern Greece and southern Bulgaria (Thrace), northern Greece and Macedonia (Paeonia and Ancient Macedonia), Iraq, Syria, Lebanon, Jordan, Israel, and Palestine, all significant ancient population centers of ancient Egypt as far west as Egypt itself.
The Achaemenid Empire was home to 50 million people in 480 BC, according to estimates.
At its height, the empire controlled over 44 percent of the world’s population, the greatest percentage for any empire in history. In Greek history, the Achaemenid Empire is regarded as the antagonist of Greek city states due to its emancipation of slaves, including Jewish exiles in Babylon, construction of infrastructures such as roads and postal systems, and use of an official language, Imperial Aramaic, throughout its territories. The empire featured a centralized, bureaucratic government led by the emperor, a strong professional army, and civil services, all of which inspired similar developments in subsequent empires. Furthermore, the Mausoleum at Halicarnassus, one of the Seven Wonders of the Ancient World, was constructed under the empire between 353 and 350 BC.
Eventual warfare on the western boundaries started with the Ionian Revolt, which exploded into the Greco-Persian Wars, and lasted until the Persians withdrew from all of their European holdings in the Balkans and Eastern Europe proper in the first part of the fifth century BC.
Alexander the Great attacked the Achaemenid Empire in 334 BC, defeating Darius III, the final Achaemenid monarch, at the Battle of Issus. Following Alexander’s untimely death, the Hellenistic Seleucid Empire took control of Iran. The Parthian Empire grew to become the dominant force in Iran in the middle of the 2nd century BC, and the century-long geopolitical arch-rivalry between Romans and Parthians started, culminating in the Roman–Parthian Wars. The Parthian Empire existed as a feudal monarchy for almost five centuries, until it was replaced by the Sassanid Empire in 224 CE. For almost four centuries, they were the world’s two most dominating powers, together with their neighboring arch-rival, the Roman-Byzantines.
The Sassanids built an empire inside the Achaemenids’ borders, with their capital at Ctesiphon. The Late Antiquity Sassanid Empire is regarded as one of Iran’s most important eras, since it impacted the culture of ancient Rome (and therefore Western Europe), Africa, China, and India, and had a significant part in the development of both European and Asian medieval art.
The Roman-Persian Wars, which raged on their western frontiers in Anatolia, the western Caucasus, Mesopotamia, and the Levant for almost 700 years, overshadowed much of the Parthian and Sassanid empires. These battles depleted both the Romans and the Sassanids, leading to their collapse at the hands of the invading Muslim Arabs.
The Kingdom of Pontus, the Mihranids, and the Arsacid dynasties of Armenia, Iberia (Georgia), and Caucasian Albania were all offshoots of the Achaemenids, Parthians, and Sassanids that founded namesake dynasties and branches in Anatolia and the Caucasus (present-day Azerbaijanand southern Dagestan).
The lengthy Byzantine-Sassanid Wars, particularly the climax Byzantine-Sassanid War of 602-628, as well as societal strife inside the Sassanid Empire, paved the ground for an Arab invasion of Iran in the 7th century. After being conquered by the Arab Rashidun Caliphate, Iran was ruled by the Arab caliphates of Umayyad and Abbasid. Following the conquest, the lengthy and slow process of Islamization of Iran started. Both converted (mawali) and non-converted (dhimmi) Iranians were discriminated against by the new Arab elite of the Rashidun and subsequently the Umayyad caliphates, being barred from government and military service and subject to a special tax known as Jizya. Gunde Shapur, home to the Academy of Gunde Shapur, the world’s most significant medical institution at the time, survived the invasion but afterwards became renowned as an Islamic institute.
The Abbasids toppled the Umayyads in 750, owing mostly to the assistance of the mawali Iranians. The bulk of the rebel force was made up of mawali, who were commanded by the Iranian commander Abu Muslim. With the advent of the Abbasid Caliphs, there was a resurgence of Iranian culture and influence, as well as a shift away from enforced Arabic traditions. The ancient Arab aristocracy’s position was eventually supplanted by an Iranian bureaucracy.
Following two centuries of Arab domination, semi-autonomous and independent Iranian kingdoms such as the Tahirids, Saffarids, Samanids, and Buyids started to emerge on the outskirts of the collapsing Abbasid Caliphate. By the Samanid period in the 9th and 10th centuries, Iranians’ attempts to reclaim their independence had been well established.
During the Islamic Golden Age, Iran’s blooming literature, philosophy, medicine, and art were important components in the creation of a new age for the Iranian civilisation. The Islamic Golden Age reached its apex in the 10th and 11th centuries, when Iran was the primary site of scientific activity. After the 10th century, the Persian language was employed alongside Arabic for scientific, philosophical, historical, musical, and medicinal works, while prominent Iranian authors such as Tusi, Avicenna, Qotb od Din Shirazi, and Biruni made significant contributions to scientific literature.
The cultural renaissance that started during the Abbasid era resulted in the reemergence of Iranian national identity, and therefore previous efforts at Arabization in Iran failed. The Iranian Shuubiyah movement served as a motivator for Iranians to reclaim their freedom from Arab invaders. The most noteworthy consequence of this movement was the survival of the Persian language, which was attested to by the epic poet Ferdowsi, who is today considered as the most important character in Iranian literature.
In the tenth century, Turkic tribes from Central Asia migrated in large numbers to the Iranian plateau. Turkic tribesmen were initially employed as mamluks (slave-warriors) in the Abbasid army, replacing Iranian and Arab components. As a consequence, the Mamluks consolidated their political authority. Large parts of Iran were temporarily ruled by the Ghaznavids, whose kings were of mamluk Turk ancestry, in 999, and then for a longer period of time by the Turkish Seljuk and Khwarezmian empires. These Turks had been Persianized and had embraced Persian administrative and ruling patterns. The Seljuks established the Sultanate of Rum in Anatolia, bringing with them their fully Persianized character. The adoption and promotion of Persian culture by Turkish monarchs resulted in the formation of a unique Turko-Persian heritage.
The Khwarezmian Empire was devastated by Genghis Khan’s Mongol armies in 1219–21. Steven R. Ward claims that “Mongol depredations and bloodshed killed up to three-fourths of the Iranian Plateau’s population, perhaps 10 to 15 million people. According to some historians, Iran’s population did not return to pre-Mongol levels until the mid-twentieth century.”
Following the disintegration of the Mongol Empire in 1256, Hulagu Khan, Genghis Khan’s grandson, founded the Ilkhanate in Iran. Timur, another conqueror, followed Hulagu’s example in 1370, creating the Timurid Empire, which lasted for another 156 years. Timur ordered the entire slaughter of Isfahan in 1387, killing an estimated 70,000 people. The Ilkhans and Timurids quickly adopted Iranian traditions and practices, preferring to surround themselves with a culture that was uniquely Iranian.
Early modern period
By the 1500s, Ismail I of Ardabil had founded the Safavid Dynasty, with Tabriz serving as its seat. Beginning with Azerbaijan, he then expanded his control over all Iranian lands, establishing intermittent Iranian hegemony over broad geographical regions and reasserting the Iranian identity throughout significant portions of Greater Iran. Iran was mainly Sunni, but Ismail forced a conversion to Shia Islam, which expanded across the Safavid lands in the Caucasus, Iran, Anatolia, and Mesopotamia. As a consequence, modern-day Iran is the world’s only recognized Shia country, with an absolute majority in Iran and the Republic of Azerbaijan, which have the world’s first and second largest number of Shia people by population percentage.
The centuries-long geopolitical and ideological conflict between Safavid Iran and the surrounding Ottoman Empire resulted in a slew of Ottoman–Persian Wars. The Safavid Era peaked under the reign of Abbas the Great, 1587–1629, defeating their Ottoman archrivals in power and establishing the empire as a major center for the sciences and arts in Western Eurasia. The Safavid Era witnessed the beginning of widespread integration of Caucasian people into new strata of Iranian society, as well as mass relocation of them inside Iran’s heartlands, which played a key part in Iran’s history for centuries to come. Following a steady collapse in the late 1600s and early 1700s due to internal disputes, constant battles with the Ottomans, and foreign intervention (most notably Russian influence), the Safavid monarchy was terminated in 1722 by Pashtun rebels who besieged Isfahan and defeated Soltan Hosein.
Nader Shah, a Khorasan ruler and military genius, successfully drove away and defeated the Pashtun invaders in 1729. He then reclaimed the annexed Caucasian provinces that had been split between Ottoman and Russian authority due to the continuing turmoil in Iran. During the reign of Nader Shah, Iran attained its largest extent since the Sassanid Empire, reestablishing Iranian control across the Caucasus as well as other significant areas of western and central Asia, and temporarily having what was probably the most powerful empire at the time.
By the late 1730s, Nader Shah had invaded India and destroyed far distant Delhi. Following the last battles in the Northern Caucasus, his territorial expansion and military victories slowed. After Nader Shah’s murder, there was a short period of civil strife and instability until Karim Khan of the Zand Dynasty came to power in 1750, ushering in an era of relative calm and prosperity.
In comparison to previous dynasties, the Zand Dynasty’s geopolitical scope was restricted. Many Iranian regions in the Caucasus achieved de facto independence and were governed locally by different Caucasian khanates. Despite their independence, they all remained dependents and vassals of the Zand monarch. The khanates ruled their domains via international trade routes between Central Asia and the West.
Following Karim Khan’s death in 1779, another civil war erupted, from which Aqa Mohammad Khan emerged, establishing the Qajar Dynasty in 1794. Following the disobedience of the Georgian subjects and their collaboration with the Russians, the Qajars seized Tblisi in the Battle of Krtsanisi in 1795 and drove the Russians out of the whole Caucasus, restoring a brief period of Iranian suzerainty over the area. The Russo-Persian wars of 1804–1813 and 1826–1828 resulted in significant irreversible territory losses for Iran in the Caucasus, which included all of Transcaucasia and Dagestan, and therefore considerable gains for the neighboring Russian Empire.
The Russians took over the Caucasus as a consequence of the 19th century Russo-Persian wars, and Iran permanently lost authority over its essential holdings in the area (including modern-day Dagestan, Georgia, Armenia, and Azerbaijan), as ratified by the treaties of Gulistan and Turkmenchay. The region north of the Aras River, which includes the modern Republic of Azerbaijan, eastern Georgia, Dagestan, and Armenia, was Iranian territory until it was conquered by Russia in the late nineteenth century.
As Iran shrunk, many Transcaucasian and North Caucasian Muslims migrated to Iran, particularly in the aftermath of the Caucasian War and the decades that followed, while Iran’s Armenians were urged to live in newly acquired Russian areas, resulting in major demographic changes.
Late modern period
The Great Famine of 1870–1871, which killed 1.5 million people—20 to 25% of Iran’s population—was responsible for the deaths of about 1.5 million people.
Between 1872 and 1905, a series of demonstrations erupted in reaction to the selling of concessions to foreigners by the Qajar shahs Nasser od Din and Mozaffar od Din, resulting in the Iranian Constitutional Revolution. During the continuing revolution, the first Iranian Constitution and the first national parliament of Iran were established in 1906. The Constitution contained formal acknowledgment of Iran’s three religious minorities, namely Christians, Zoroastrians, and Jews, which has remained a foundation in Iranian law since that time.
The constitutional movement’s fight lasted until 1911, when Mohammad Ali Shah was defeated and forced to abdicate. Under the guise of restoring order, the Russians invaded Northern Iran in 1911 and remained in the area for the next few years. During World War I, the British controlled most of Western Iran until withdrawing completely in 1921. Furthermore, as part of the Middle Eastern Theatre of World War I, the Persian Campaign began in Northwestern Iran after an Ottoman invasion. As a consequence of Ottoman conflicts across the border, the Ottoman forces murdered a significant number of Iranian Assyrians, particularly in and around Urmia. Aside from Aqa Mohammad Khan’s reign, the Qajar era is described as a century of misrule.
The Qajar Dynasty was deposed in 1921 by Reza Khan of the Pahlavi Dynasty, Prime Minister of Iran and former commander of the Persian Cossack Brigade, who became the new Shah.
Reza Shah was compelled to abdicate in 1941 in order for his son, Mohammad Reza Pahlavi, to construct the Persian Corridor, a vast supply line that would continue until the conclusion of the war. The presence of so many foreign soldiers in the country also resulted in the creation of two puppet governments in the country, the Azerbaijan People’s Government and the Republic of Mahabad, both supported by the Soviet Union. As the Soviet Union refused to surrender the seized Iranian land, the Iran crisis of 1946 erupted, resulting in the collapse of both puppet governments and the departure of the Soviets.
Mohammad Mosaddegh was elected Prime Minister in 1951. He gained tremendous popularity in Iran after nationalizing the country’s petroleum sector and reserves. He was ousted in the 1953 Iranian coup d’état, a clandestine Anglo-American operation that was the first time the US overthrew a foreign government during the Cold War.
Following the coup, the Shah became more authoritarian and sultanistic, and Iran began a period of contentious close ties with the US and other foreign countries. While the Shah modernized Iran and claimed to maintain it as a completely secular state, his secret police, the SAVAK, employed arbitrary arrests and torture to suppress all kinds of political dissent.
Ayatollah Ruhollah Khomeini became a vocal opponent of the Shah’s White Revolution, openly condemning the regime. Khomeini was imprisoned for 18 months after being captured. Khomeini openly denounced the US authorities after his release in 1964. He was exiled by the Shah. He traveled to Turkey first, then to Iraq, and ultimately to France.
Because of the 1973 increase in oil prices, the Iranian economy was inundated with foreign money, causing inflation. By 1974, Iran’s economy was suffering double-digit inflation, and despite numerous major initiatives to modernize the nation, corruption was widespread, resulting in massive waste. By 1975 and 1976, an economic downturn had resulted in increasing unemployment, particularly among the millions of young people who had moved to Iran’s cities in search of construction work during the boom years of the early 1970s. By the late 1970s, many of these individuals had become tired of the Shah’s rule and started to organize and participate in anti-government demonstrations.
After the 1979 Revolution
The 1979 Revolution, also known as the Islamic Revolution, started in January 1978 with the first significant anti-Shah protests.
Mohammad Reza Pahlavi left the nation after a year of protests and rallies paralyzed the country and its economy, and Ruhollah Khomeini returned from exile to Tehran in February 1979, establishing a new administration. Following a referendum, Iran declared itself an Islamic Republic in April 1979. In December 1979, a second vote adopted a theocratic constitution.
The 1979 Kurdish revolt, coupled with protests in Sistan and Baluchestan Province and other regions, sparked rapid national upheavals against the new administration. The new Islamic administration violently suppressed these protests over the following few years. The new administration set about cleansing itself of non-Islamist political opponents as well as Islamists who were deemed insufficiently extreme. Although nationalists and Marxists originally collaborated with Islamists to depose the Shah, the Islamic regime afterwards killed tens of thousands of people.
On November 4, 1979, a group of students stormed the United States Embassy and held 52 employees and citizens hostage because the US refused to send Mohammad Reza Pahlavi to Iran for prosecution in the new regime’s court and execution. Attempts by the Jimmy Carter administration to negotiate the release of the hostages, as well as a botched rescue attempt, aided in the removal of Carter from office and the election of Ronald Reagan. As a consequence of the Algiers Accords, the remaining hostages were ultimately released on Jimmy Carter’s last day in office.
The Cultural Revolution started in 1980, with the temporary closure of universities for three years in order to conduct an examination and cleaning of the educational and training system’s cultural policies.
The Iran–Iraq War started on September 22, 1980, when the Iraqi army invaded Iranian Khuzestan. Despite numerous early gains by Saddam Hussein’s troops, by mid 1982, Iranian forces had effectively driven the Iraqi army back into Iraq. In July 1982, with Iraq on the defense, Iran decided to invade Iraq and launch a series of offensives to seize Iraqi land and capture cities such as Basra. The conflict lasted until 1988, when the Iraqi army defeated the Iranian forces inside Iraq and drove the remaining Iranian soldiers over the border. As a result, Khomeini agreed to a cease-fire mediated by the United Nations. Total Iranian fatalities were estimated to be 123,220–160,000 KIA, 60,711 MIA, and 11,000–16,000 civilians slain throughout the conflict.
Following the Iran–Iraq War in 1989, Akbar Hashemi Rafsanjani and his government focused on a pragmatic pro-business strategy of rebuilding and expanding the economy without abandoning the revolution’s principles. Rafsanjani was replaced in 1997 by Mohammad Khatami, a moderate reformer whose administration tried, but failed, to make the nation more free and democratic.
Mahmoud Ahmadinejad, a conservative populist contender, was elected president in 2005. During the 2009 Iranian presidential election, the Interior Ministry reported that incumbent President Mahmoud Ahmadinejad had received 62.63 percent of the vote, with Mir-Hossein Mousavi receiving 33.75 percent. Allegations of massive irregularities and fraud sparked demonstrations in Iran and major cities across the world during the 2009 Iranian presidential election.
On June 15, 2013, Hassan Rouhani was elected President of Iran, beating Mohammad Bagher Ghalibaf and four other contenders. The election of new Iranian President Hassan Rouhani has improved Iran’s ties with neighboring nations.