History of Iran in Timeline

By Popular Timelines Editorial Team · Updated: July 19, 2026

Iran, formerly known as Persia, is a sovereign state in Western Asia with a rich history spanning thousands of years. Located at the crossroads of major trade routes, it possesses a unique cultural identity characterized by its Persian heritage and Islamic influence. Governed as a theocratic republic since the 1979 Islamic Revolution, Iran plays a significant role in Middle Eastern geopolitics. The nation holds one of the world's largest proven oil and natural gas reserves, which serves as a cornerstone of its economy. Despite significant international tensions and economic sanctions, Iran maintains a robust domestic industry, a well-educated population, and a prominent position in regional diplomacy. Its geography is diverse, featuring rugged mountain ranges, vast central deserts, and significant coastlines along the Persian Gulf and Caspian Sea, all of which contribute to its strategic importance and complex geopolitical status on the global stage.

1905: Beginning of the Persian Constitutional Revolution

In 1905, the Persian Constitutional Revolution began, marking the start of a movement that would eventually lead to the formation of the first Iranian parliament.

1911: Conclusion of the Persian Constitutional Revolution

By 1911, the Persian Constitutional Revolution reached its conclusion, having successfully resulted in the establishment of the Iranian parliament.

1921: The 1921 coup d'état

In 1921, a significant coup d'état took place in Iran, which ultimately triggered the end of the Qajar dynasty and paved the way for the establishment of the Pahlavi dynasty.

1925: Establishment of the Pahlavi Dynasty

In 1925, Reza Shah ousted the last Qajar monarch, effectively establishing the Pahlavi dynasty and marking a new era in Iranian governance.

1935: Official Change of Name from Persia to Iran

In 1935, during an international Nowruz gathering, Reza Shah Pahlavi requested that the international community officially use the endonym "Iran" instead of "Persia" to refer to his nation, leading to the standardization of "Iran" and "Iranian" in global formal correspondence.

1935: Official Terminology Shift from Persia to Iran

In 1935, the Iranian state transitioned to using 'Iran' as the primary international name for the country, marking a significant reclamation of national identity that was rooted in the region's ancient heritage.

August 1941: Operation Countenance

In August 1941, Allied forces consisting of the United Kingdom and the Soviet Union launched Operation Countenance, invading Iran after the Iranian government refused to expel German residents. The Allies quickly overwhelmed the Iranian military, seeking to secure supply lines and prevent Axis influence in the region.

1941: Anglo-Soviet Invasion of Iran

During 1941, an Anglo-Soviet invasion of Iran occurred, which resulted in the ascension of Mohammad Reza Pahlavi to the throne following his father's departure.

1941: Abdication of Reza Shah

In 1941, Reza Shah was forced to abdicate his position following the Anglo-Soviet invasion of Iran, ending his sixteen-year rule.

1943: Tehran Conference

In 1943, Allied leaders Joseph Stalin, Franklin D. Roosevelt, and Winston Churchill met at the Tehran Conference to issue the Tehran Declaration, which served as a formal guarantee regarding the maintenance of Iran's post-war independence and national boundaries.

1951: Nationalization of the Iranian Oil Industry

In 1951, the Iranian parliament, guided by Prime Minister Mohammad Mosaddegh, voted to nationalize the British-controlled oil industry, an act that triggered the Abadan Crisis and significant economic pressure from the British government.

1952: Removal and Re-appointment of Prime Minister Mosaddegh

During 1952, Prime Minister Mohammad Mosaddegh was initially removed from power; however, due to a massive popular uprising advocating for his leadership, he was quickly re-appointed to his position by the Shah.

August 1953: Failed Coup and Shah's Exile

In August 1953, following a failed military coup attempted by Colonel Nematollah Nassiri of the Imperial Guard, Prime Minister Mohammad Mosaddegh forced the Shah to flee Iran into a brief period of exile.

1953: Anglo-American Coup

In 1953, an Anglo-American coup was orchestrated against Mohammad Mosaddegh following his government's attempts to nationalize the Iranian oil industry.

1959: Shah Mohammad Reza Pahlavi Permits Use of Persia and Iran

In 1959, Shah Mohammad Reza Pahlavi officially declared that both 'Persia' and 'Iran' were acceptable for use in formal correspondence, acknowledging the historical weight of both titles.

1978: Heightened Civil Unrest and Black Friday

During 1978, the Shah's popularity plummeted, leading to widespread daily demonstrations across Iran. In response to the persistent protests, the Shah implemented martial law, culminating in a violent confrontation known as Black Friday, where security forces opened fire on massive crowds of protestors.

March 1979: 1979 Iranian Islamic Republic Referendum

On March 31, 1979, Iran held a national referendum in which 99.31% of voters supported transitioning from a monarchy to an Islamic republic, setting the stage for the creation of a new theocratic constitution.

November 1979: Seizure of the US Embassy in Tehran

On 4 November 1979, Iranian students seized the US embassy, taking 52 personnel as hostages and labeling the location a 'den of spies' due to fears of a potential coup to reinstate the Shah.

December 1979: Khomeini Becomes Supreme Leader

In December 1979, following the ratification of a theocratic constitution, Ayatollah Khomeini officially assumed the role of Supreme Leader, leading to the Islamization of schools, nationalization of industries, and a departure from Western-influenced economic policies.

1979: The Iranian Revolution

The monarchy was overthrown during the 1979 Iranian Revolution, leading to the creation of the Islamic Republic of Iran under the leadership of Ruhollah Khomeini.

September 1980: Invasion of Khuzestan

On 22 September 1980, Iraqi forces under Saddam Hussein launched a surprise invasion of Iran in the Khuzestan region, marking the official beginning of the Iran–Iraq War.

1980: Start of the Iran–Iraq War

Iraq initiated an invasion of Iran in 1980, which triggered a prolonged eight-year military conflict known as the Iran–Iraq War.

1980: Beginning of the Cultural Revolution in Iran

Starting in 1980 and lasting until 1983, the Cultural Revolution in Iran was initiated to purge opposition to Islamic values within the country.

January 1981: End of the Iran Hostage Crisis

In January 1981, the 444-day hostage crisis concluded as the 52 American embassy personnel, who had been held since November 1979, were finally released.

1982: Iranian Counter-offensive

By 1982, Iranian military forces successfully repelled the Iraqi army and forced them to retreat back across the border into Iraq.

1982: Iran Massacres

During the period of the Cultural Revolution, the 1981-1982 Iran massacres occurred as part of the broader efforts to suppress opposition to Islamic values.

1983: Conclusion of the Cultural Revolution

The Cultural Revolution in Iran, which began in 1980, officially concluded in 1983 after successfully purging opposition to Islamic values.

1988: End of the Iran-Iraq War

In 1988, after eight years of conflict, Ayatollah Khomeini formally accepted a United Nations-mediated truce, effectively ending the Iran-Iraq War in a stalemate. The prolonged war, which concluded in 1988, resulted in a staggering death toll of approximately 500,000 people and involved the extensive use of chemical weapons by Saddam Hussein.

1989: Transition of Power and Constitutional Reform in Iran

In 1989, prior to his death, Ayatollah Khomeini established a 25-man Constitutional Reform Council, which subsequently appointed Ali Khamenei as the new Supreme Leader of Iran and implemented significant revisions to the nation's constitution.

1991: Historical context of direct state attacks on Israel

The year 1991 serves as the historical reference point for the last time a foreign state directly attacked Israel prior to the Iranian retaliation in April 2024.

1997: Transition of power to Mohammad Khatami

In 1997, moderate reformist Mohammad Khatami succeeded Akbar Rafsanjani as President of Iran, ushering in a new governmental focus on freedom of expression, improved diplomatic relations with the European Union and Asia, and a continued commitment to free market policies and foreign investment.

2000: Decline of the Kura–Araxes Culture

Around 2000 BC, the Kura–Araxes culture, which had been prevalent throughout northwestern Iran and the Caucasus since approximately 3400 BC, reached the end of its established presence in the region.

2005: Election of Mahmoud Ahmadinejad

In 2005, the Iranian presidential election resulted in the victory of Mahmoud Ahmadinejad, a conservative populist known for his nationalist stance, controversial nuclear policies, and confrontational foreign policy towards Western and regional powers. He later became the first president summoned to parliament for questioning.

2013: Election of Hassan Rouhani

In 2013, Hassan Rouhani was elected as the president of Iran. As a centrist and reformist leader, his presidency focused on increasing personal freedoms, enhancing access to information, expanding women's rights, and utilizing conciliatory diplomacy to mend international relations.

2015: Joint Comprehensive Plan of Action

In 2015, Iran, the P5+1, and the EU reached the Joint Comprehensive Plan of Action in Vienna, an agreement designed to lift economic sanctions on Iran in return for restrictions on its uranium enrichment program.

2017: Ebrahim Raisi's first presidential bid

In 2017, hardliner Ebrahim Raisi participated in the presidential election but was unsuccessful in his bid to secure the presidency.

2018: US Withdrawal from JCPOA

During 2018, the United States, under the administration of President Donald Trump, officially withdrew from the nuclear deal, leading to the imposition of new economic sanctions and moving Iran toward nuclear threshold status.

2020: Assassination of Qasem Soleimani and Subsequent Retaliation

In 2020, IRGC general Qasem Soleimani was assassinated by the United States, leading to significant escalation in tensions. Iran responded with a large-scale ballistic missile attack on US airbases in Iraq, resulting in 110 American personnel sustaining brain injuries.

2021: Ebrahim Raisi succeeds Rouhani

In 2021, Ebrahim Raisi ran for president again and successfully succeeded Hassan Rouhani to become the President of Iran.

2022: Iranian support for the invasion of Ukraine

During 2022, Iran took a stance supporting the Russian invasion of Ukraine, marking a significant development in its foreign policy alignment.

2023: Weakening of Iranian Regional Allies

Starting in 2023, the progressive weakening of Iran's key regional allies and proxies led to the government in Tehran becoming increasingly isolated and politically vulnerable.

April 2024: Direct Iranian military escalation against Israel

Following an April 2024 Israeli airstrike on the Iranian consulate in Damascus, Iran launched an unprecedented retaliatory attack on Israel using drones and missiles, marking the largest drone strike in history and the first direct state-on-state attack on Israel since 1991.

May 2024: Death of Raisi and Presidential Election

In May 2024, Iranian President Ebrahim Raisi died in a helicopter crash, which led to a subsequent presidential election that resulted in the victory of reformist candidate Masoud Pezeshkian.

May 2025: Mass Deportation of Afghan Migrants

In May 2025, the Iranian government issued an order requiring the mass deportation of approximately four million Afghan migrants and refugees currently residing within Iran's borders.

2025: Escalation of Nuclear Enrichment Program

During early 2025, Iran rapidly accelerated its nuclear program to levels that experts argued lacked any plausible civilian justification, leading to stalled negotiations with the United States and the activation of a new enrichment facility in June 2025 following IAEA non-compliance findings.

2025: Twelve-Day War and Civil Protests

In 2025, Israeli strikes on Iranian territory escalated regional tensions into the Twelve-Day War, subsequently fueling the largest internal protests in the country since 1979 amidst an economic crisis.

2026: Escalated War and Leadership Succession

Following the 2026 assassination of supreme leader Ali Khamenei, the United States and Israel engaged in war with Iran, leading to the election of Mojtaba Khamenei as the new supreme leader.

8 January 2020: Shootdown of Ukraine International Airlines Flight 752

On 8 January 2020, the Islamic Revolutionary Guard Corps shot down Ukraine International Airlines Flight 752, resulting in the deaths of 176 civilians. The incident triggered widespread protests in Iran, and the government eventually admitted to the use of a surface-to-air missile following an international investigation.