Iran: timeline and key events
6th century BC
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Politics
Cyrus the Great founds the Persian Empire
Around 550 BC, Cyrus II overthrew the king of the Medes and founded the Achaemenid Empire, which became the largest of its time. After taking Babylon in 539 BC, he allowed deported peoples, including the Jews, to return to their homelands.
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Culture
Darius I founds Persepolis
Darius I began building Persepolis, the ceremonial capital of the Achaemenid Empire. He organised the empire into satrapies and gave it a Royal Road linking Susa to Sardis.
4th century BC
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War
Alexander the Great conquers Persia
Having defeated Darius III at Issus and then at Gaugamela, Alexander the Great burned Persepolis; the death of Darius, murdered by his own satraps, brought the Achaemenid Empire to an end. After Alexander, Iran passed to the Seleucids and then to the Parthians.
3rd century
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Politics
Founding of the Sasanian Empire
Ardashir I overthrew the last Parthian king and founded the Sasanian dynasty, which made Zoroastrianism a state religion. A rival of Rome and then Byzantium for four centuries, the empire even captured Emperor Valerian in 260.
7th century
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Religion
Arab conquest and the fall of the Sasanians
Defeated at Qadisiyya and then at Nahavand, the Sasanians collapsed before the Arab armies; the last king, Yazdegerd III, was killed in 651. Iran gradually converted to Islam but kept its language, Persian, and a strong cultural identity.
11th century
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Culture
Ferdowsi completes the Book of Kings
The poet Ferdowsi completed the Shahnameh, an epic of some 50,000 couplets recounting the legendary and historical past of Iran up to the Arab conquest. The work played a central role in preserving the Persian language.
16th century
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Religion
Ismail I founds the Safavid dynasty
Crowned shah in Tabriz, Ismail I reunified Iran and imposed Twelver Shiism as the state religion. This choice shaped the country's religious identity, which has been predominantly Shia ever since.
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Culture
Isfahan, capital of Shah Abbas
Shah Abbas I, the most illustrious of the Safavid rulers, made Isfahan his capital and adorned it with monuments around Naqsh-e Jahan Square. A Persian saying of the time declared that “Isfahan is half the world”.
20th century
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Politics
Constitutional Revolution
Under pressure from a broad movement of merchants, clerics and intellectuals, Mozaffar ad-Din Shah granted a parliament, the Majlis, and on 30 December signed the country's first constitution. It was one of the first constitutional revolutions in Asia.
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Economy
Discovery of oil
British prospectors struck oil at Masjed Soleyman, the first discovery of its kind in the Middle East. The Anglo-Persian Oil Company, founded the following year, controlled this wealth for four decades, and it became a central issue in Iranian history.
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Politics
Rise of the Pahlavi dynasty
The Majlis deposed the Qajars and proclaimed the army officer Reza Khan shah, under the name Reza Shah Pahlavi. He modernised the state at a forced pace and in 1935 asked that the country be called Iran in international relations.
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Politics
Fall of Mosaddegh
Two years after nationalising Iranian oil, Prime Minister Mohammad Mosaddegh was overthrown in a coup organised with the backing of the CIA and MI6, a role acknowledged by Washington in 2013. The shah then strengthened his personal rule.
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Politics
Islamic Revolution
After months of demonstrations, the shah left Iran in January and Ayatollah Ruhollah Khomeini returned from exile on 1 February; the imperial regime fell on 11 February. Approved by referendum, the Islamic Republic was proclaimed on 1 April, and Khomeini became its Supreme Leader.
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Politics
Hostage crisis at the US embassy
Islamist students stormed the United States embassy in Tehran and held 52 American diplomats and staff for 444 days. The crisis, which ended on 20 January 1981, caused a lasting rupture in relations between Washington and Tehran.
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War
Iran-Iraq War
Saddam Hussein's Iraq invaded Iran, triggering an eight-year war marked by trench warfare, the bombing of cities and Iraq's use of chemical weapons. The conflict, ended by a ceasefire in August 1988, left several hundred thousand dead.
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Politics
Ali Khamenei succeeds Khomeini
On the death of Ayatollah Khomeini, the Assembly of Experts chose Ali Khamenei, then President of the Republic, to succeed him as Supreme Leader. He held the post until his death in 2026, alongside presidents who were by turns conservative and reformist, such as Mohammad Khatami, elected in 1997.
21st century
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Politics
Vienna nuclear agreement
Iran concluded an agreement with the United States, China, Russia, France, the United Kingdom and Germany limiting its nuclear programme in exchange for the lifting of sanctions. The United States withdrew in 2018 under President Donald Trump and reimposed its sanctions.
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Society
Death of Mahsa Amini and the “Woman, Life, Freedom” movement
The young Kurdish woman Mahsa Amini died after being arrested by the morality police for allegedly wearing her headscarf improperly. Her death sparked a vast protest movement, which the authorities suppressed; in 2023, the imprisoned activist Narges Mohammadi was awarded the Nobel Peace Prize.
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War
Twelve-Day War with Israel
On 13 June, Israel struck Iranian nuclear and military sites and killed several senior officials; Iran retaliated with missile fire on Israel. The United States bombed three nuclear sites on 22 June, before a ceasefire on 24 June.
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War
War with the United States and Israel
After a vast protest movement was harshly suppressed between December 2025 and January 2026, the United States and Israel launched an offensive against Iran on 28 February; Supreme Leader Ali Khamenei was killed on the first day. In March, the Assembly of Experts chose his son Mojtaba Khamenei to succeed him.
