On March 21, 1935, Reza Shah Pahlavi sent a letter to the world's foreign embassies with a simple request: stop calling his country "Persia." From this point forward, it would be known as Iran.
The message seemed almost ceremonial, a matter of diplomatic housekeeping, the kind of administrative tidying that rarely makes headlines. But behind this quiet directive lay something far more ambitious: a fundamental reimagining of national identity, a deliberate break from colonial history, and the opening move in a geopolitical game centered on oil that has never stopped being played.
A Country That Already Had a Name
To understand why the renaming mattered, you first need to understand why "Persia" was never really the country's name in the first place, at least not to the people who lived there.
"Persia" is an exonym: a name given by outsiders. It derives from the ancient Greek word "Persis", which referred specifically to the southwestern province of Pars (modern-day Fars), the heartland of the old Achaemenid Empire founded by Cyrus the Great in the sixth century BCE. When Greek historians — above all Herodotus — wrote about the vast empire to their east, they called it Persia, after this one region. The name stuck in the Western world for over two millennia.
Inside the country, however, people had always used a different word: Iran. The term comes from the ancient Iranian "Airyanem", meaning roughly "Land of the Aryans", not in the racial sense later twisted by Nazi ideology, but in the older linguistic and cultural sense of the word, referring to the Indo-Iranian peoples and their shared heritage. The name appears in the Avesta, the sacred texts of Zoroastrianism, and was used by rulers as far back as the Sasanian Empire in the third century CE. The Sasanian king Ardashir I, founder of that dynasty, titled himself "King of Kings of Aryans" on his coins and in the royal inscriptions at Naqsh-e Rustam. The great Persian epic the Shahnameh, written by the poet Ferdowsi around 1000 CE, also uses "Iran" throughout. For Iranians, it was simply their country's name. The Western world just hadn't been using it.
The request Reza Shah made in 1935 was not an invention; it was a correction.
The Man Behind the Decree
Reza Shah Pahlavi was not born into power. He came from a modest military family in the northern Mazandaran province, lost his father as an infant, and was raised partly by an uncle who served in the Persian Cossack Brigade, the Russian-trained military force that served as the backbone of Qajar-era Iran's army. Joining the Cossacks at around fifteen, he rose through the ranks on the strength of his intelligence, physical presence (he was reportedly an imposing figure), and fierce ambition.
By early 1921, with the Qajar dynasty weak and Iran's sovereignty fraying in all directions, Russian troops occupying the north, British interests dominating the south, and tribal rebellions across the interior, Reza Khan, as he was then known, led a force of 1,200 Cossack soldiers from Qazvin toward Tehran and seized control of the capital in a coup. He appointed himself Minister of War. Two years later, he became Prime Minister. And on December 12, 1925, the Iranian parliament, the Majlis, voted to depose the last Qajar Shah and crown Reza Khan as the first Shah of a new royal dynasty, the Pahlavis, a name deliberately chosen to evoke the Middle Persian language of the ancient Sasanian Empire.
His model was Kemal Atatürk, the Turkish leader who had, from the ruins of the Ottoman Empire, conjured a modernized, secular Turkish republic almost by sheer will. Reza Shah admired Atatürk's discipline, his ruthlessness with tradition, and his conviction that a country could be remade from the top down. He reportedly considered turning Iran into a republic, as Atatürk had done in Turkey, but backed away when it became clear the Shia clergy would never accept it. So he kept the monarchy and pursued modernization by other means.
In the decade that followed, Reza Shah transformed the country at a remarkable pace. He built a 1,392-kilometer trans-Iranian railway connecting the Persian Gulf with the Caspian Sea, paid for without foreign loans, using funds raised from a national tea and sugar tax. He established secular schools, sent thousands of young Iranians abroad on state scholarships (mostly to the United States and Europe), founded the University of Tehran, built roads, and set up a national bank. He banned traditional tribal clothing and, in 1936, issued the Kashf-e hijab decree banning the veil, a move that put him in direct conflict with the Shia clergy and remains controversial to this day. He even criminalized photography of anything he considered "backward", camels, ghettos, and women in chadors, because he was acutely conscious of the country's image in Western eyes.
The name change was entirely in keeping with this program. For Reza Shah, "Persia" belonged to the world of exoticism and Western condescension, a name that conjured carpets and poetry and ancient ruins, but not sovereignty or industrial power. "Iran" was the name Iranians used for themselves. Demanding the world use it too was an act of cultural assertion, a statement that this country would define itself on its own terms.
The Day the Request Was Made
The formal decree was actually sent a few months before the official date. In December 1934, the Persian Ministry of Foreign Affairs circulated a memorandum to all foreign diplomatic missions in Tehran, requesting that the terms "Iran" and "Iranian" be used in official correspondence starting from March 21, 1935. That date was chosen deliberately: it was Nowruz, the Persian New Year, the first day of spring in the Iranian calendar. A new year, a new name.
Not everyone was immediately cooperative. The British, with their long habit of calling the country Persia, initially dragged their feet. During the Second World War, Winston Churchill actually asked the Iranian government to allow the Allied powers to continue using "Persia" for the duration of the conflict, on the practical grounds that "Iran" and "Iraq", both occupied by British forces at various points, sounded dangerously similar. The Iranian government agreed to permit interchangeable use, and in 1959, under Reza Shah's son and successor Mohammad Reza Pahlavi, it was officially declared that both names were acceptable. But the drift was already well underway. "Iran" had become the dominant term, and by the time the Islamic Republic was established in 1979, the country's official name, the Jomhuri-ye Eslāmi-ye Irān, enshrined it permanently.
In recent decades, the name change has sometimes been mischaracterized as a gesture toward Nazi Germany, the argument being that by adopting "Iran," meaning "Land of the Aryans," Reza Shah was cozying up to Hitler's ideology. This interpretation does not hold up. The word "Aryan" as used in the Iranian context predates Nazism by thousands of years, and "Iran" had been the country's name internally since at least the Sasanian period. There is no credible historical evidence that the renaming was motivated by Nazi sympathies. What is true is that Germany had become Iran's largest trade partner by 1940, and Reza Shah admired German industriousness and discipline. He also used German, Scandinavian, and American technicians, deliberately avoiding British and Soviet expertise, to build his railway. But his relationship with Nazi Germany was pragmatic and transactional, not ideological. When the British and Soviets invaded Iran in August 1941 and demanded he expel German nationals, he refused, and was forced to abdicate as a result. Whether he admired Hitler personally remains a matter of historical debate.
Oil Beneath the Surface
While Reza Shah was remaking his country's public identity, something far more consequential had already been set in motion beneath its soil.
In May 1908, after seven years of increasingly desperate searching, a British geologist named George Reynolds struck oil at Masjed Soleyman, in the southwestern province of Arabistan (today's Khuzestan). It was, at the time, the largest oil discovery ever made in the Middle East — and it would reshape the region's history for the next century and beyond.
The discovery had been funded by a British millionaire named William Knox D'Arcy, who in 1901 had paid the Qajar Shah £20,000 in cash and £20,000 in shares for a 60-year concession covering most of the country. In return, D'Arcy and his investors would keep 84 percent of the profits; Iran's government would receive 16 percent. Within a year of the 1908 discovery, the Anglo-Persian Oil Company (APOC) was formally incorporated with £2 million in capital. A 145-mile pipeline was built to the coast, and the Abadan refinery opened in 1912. By the 1940s it had grown into the largest oil refinery in the world.
In 1914, the British government purchased a 51 percent controlling stake in APOC, partly to secure a guaranteed fuel supply for the Royal Navy as it transitioned from coal to oil. The arrangement that followed was enormously profitable for Britain. Through the 1920s, 1930s, and 1940s, British cars, trucks, buses, factories, and warships ran on Iranian oil. Meanwhile, Iranian workers at Abadan were paid wages of around 50 cents a day, lived in a shantytown without running water or electricity called Kaghazabad ("Paper City"), and were excluded from management roles. In 1947, the AIOC, which by then had been renamed the Anglo-Iranian Oil Company, acknowledging the country's new name, reported after-tax profits of £40 million and paid Iran just £7 million of it. The deal was not so much a partnership as a legal structure for extraction.
In 1935, the year of the renaming, the APOC became the AIOC to reflect the country's new official name. The change of letters was an acknowledgement of the new identity. But the underlying power structure, British control and Iranian subordination, remained exactly the same.
The Man Who Said No
The anger that had been building for decades finally found its champion in Mohammad Mossadegh, lawyer, politician, and leader of the National Front party, whose slight frame and theatrical courtroom manner concealed a steely nationalist conviction.
On March 15, 1951, the Iranian Majlis voted to nationalize the Anglo-Iranian Oil Company. On April 28, 1951, Mossadegh was elected Prime Minister. Days later, the Senate ratified the nationalization bill unanimously. The AIOC's assets were seized, and the National Iranian Oil Company (NIOC) was formed in its place.
The British response was swift and severe. They withdrew their technicians from Abadan, making it nearly impossible to maintain refinery operations. They blockaded Iranian oil exports, making it clear to tanker owners worldwide that oil purchased from Iran would not be accepted on international markets. They froze Iranian assets in British banks, cut off vital imports, and took the case to the International Court of Justice. The Abadan refinery, once the world's busiest, ground to a halt. Iran's oil production fell from 242 million barrels in 1950 to just 10.6 million barrels in 1952. The country's economy hemorrhaged.
Mossadegh refused to back down. He toured the United States, arguing Iran's case before the United Nations and the World Court. He won some sympathy; American President Harry Truman was skeptical of British imperialism, but not enough to matter. The British turned to Washington with a different argument: Mossadegh's Iran was economically weakened, politically unstable, and in danger of falling to communism. This was the early Cold War; the argument landed. In the summer of 1953, the CIA and MI6 launched Operation Ajax (known in London as Operation Boot), the first time the CIA had ever orchestrated the overthrow of a foreign government. Paid crowds were mobilized, key military and political figures were bribed, and on August 19, 1953, tanks rolled to Mossadegh's residence. He was arrested, tried for treason, sentenced to three years' solitary confinement in a military prison, and then kept under house arrest until his death in 1967.
The message delivered to the world was unambiguous: oil was not merely a commodity. It was a geopolitical asset of the first order, and the countries that controlled the infrastructure were not prepared to yield it quietly.
From Modernisation to Revolution
The coup of 1953 restored the Shah, Reza Shah's son, Mohammad Reza Pahlavi, to the Peacock Throne with firmly pro-Western leanings and a firmer grip on power than before. The CIA's internal report on Operation Ajax described it as "a success." In Iran, the memory of what had happened would never fade.
Mohammad Reza Shah continued his father's program of modernization, accelerating it dramatically after the oil price boom of the 1970s. Under the so-called White Revolution of 1963, he launched land reform, women's suffrage, and a massive expansion of education and infrastructure. By the mid-1970s, flush with oil revenues, he was pursuing the most ambitious military and industrial build-up in the country's history. He celebrated the 2,500-year anniversary of the Persian Empire with a spectacular and wildly expensive ceremony at Persepolis in 1971, hosting heads of state from around the world at a party widely criticized as an exercise in monarchic vanity while much of the country remained poor.
The contradictions were becoming impossible to ignore. Rapid modernization had created a large, educated urban middle class, many of whom were excluded from political life by the Shah's increasingly autocratic rule. The secret police, SAVAK, trained and supported by the CIA, were feared throughout the country. The gap between the urban elite and the rural poor was vast. The Shia clergy, sidelined and sometimes openly persecuted under Pahlavi rule, nursed long grievances. And in exile in Iraq and then France, an elderly cleric named Ayatollah Ruhollah Khomeini was broadcasting cassette-taped sermons back into Iran, channeling all of this discontent into a religious framework that called for the Shah's removal and the establishment of an Islamic state.
The revolution, when it came in 1978–1979, happened with astonishing speed. Strikes crippled oil production. Massive street demonstrations shook every major city. In January 1979, the Shah left the country, ostensibly for medical treatment, and never returned. On February 1, 1979, Khomeini flew into Tehran from Paris. Within weeks the monarchy was abolished, and the Islamic Republic of Iran was declared.
The revolution immediately transformed Iran's relationship with the global energy market. The country withdrew from its role as a pillar of Western energy supply and expelled American and British personnel from its oil industry. The NIOC, Mossadegh's old creation, now operated entirely under Iranian control. Iranian oil production, which had reached nearly 6 million barrels a day before the revolution, crashed to under 2 million. Global oil prices doubled, then doubled again. The second oil shock of 1979 pushed Western economies into recession. The revolution had not merely changed a government; it had detonated a bomb in the middle of the global energy system.
The Strait at the Centre of the World
Geography, more than anything else, is what gives Iran its enduring leverage over global energy markets. At the mouth of the Persian Gulf, where the Gulf narrows to a passage just 34 kilometers wide at its tightest point, lies the Strait of Hormuz, arguably the most strategically important stretch of water on the planet.
Through this narrow corridor flows roughly 20 million barrels of oil per day, approximately 20 percent of total global petroleum consumption and 27 percent of all seaborne oil trade. Almost every drop of crude exported by Saudi Arabia, Iraq, Kuwait, Qatar, and the UAE passes through it. In 2024, an estimated 84 percent of that crude was heading to Asian markets, primarily China, India, Japan, and South Korea. These four countries alone accounted for 69 percent of all crude oil and condensate flows through the strait. The Strait also carries roughly 20 percent of global liquefied natural gas (LNG) trade, most of it originating from Qatar's enormous gas fields.
What makes Hormuz so dangerous as a chokepoint is the near-total absence of alternatives. There are pipeline routes that bypass the strait, Saudi Arabia's East-West Pipeline and a UAE pipeline to the port of Fujairah, but their combined capacity falls far short of what passes through the water. In 2018, some 21 million barrels a day transited the strait, at prices that put the value of that daily flow at over $1.2 billion. A serious disruption would not just raise prices; it would create acute energy emergencies across Asia and send shockwaves through every economy on earth.
Iran sits on the northern shore of the Strait for its entire length. Its Revolutionary Guards control naval operations throughout the Persian Gulf. It is, in the most literal possible sense, the keeper of the gate, and it has never stopped reminding the world of this fact.
A Name That Became a Strategy
Reza Shah's decree on March 21, 1935, was not, by itself, the cause of everything that followed. The oil was already there. The foreign concessions were already signed. The resentments were already accumulating. But the renaming was the moment a country declared, in its own voice, that it intended to be seen differently, as a sovereign actor in a world that had treated it as a resource to be managed rather than a nation to be respected.
Every major confrontation Iran has had with the outside world since 1935 carries the DNA of that original declaration. The nationalization of the oil company in 1951 was Mossadegh saying what Reza Shah had implied: our resources belong to us. The 1953 coup was the world's response: not yet. The 1979 revolution was the final, seismic assertion: they were wrong to think they could hold that position forever. And every subsequent threat to close the Strait of Hormuz, from the earliest Cold War whispers to the events actively unfolding in the region today, is the same claim made in the hardest possible language.
There is an irony running through all of this that is worth pausing on. The Anglo-Persian Oil Company changed its own name to the Anglo-Iranian Oil Company in 1935, the same year Reza Shah made his request. Even the company that had been extracting Iran's wealth for decades acknowledged the new identity. The name changed. The power structure did not, not until Mossadegh forced the issue with a vote in parliament.
Today "Persia" and "Iran" coexist in common usage, but with different registers. "Persian" is the word for the language, the cuisine, the rugs, the classical poetry of Rumi and Hafez, and the cultural inheritance that stretches back thousands of years. "Iran" is the word for the state, the geopolitics, the nuclear negotiations, the oil sanctions, and the Revolutionary Guards. The split in usage maps fairly precisely onto the split between the country the outside world finds easy to admire and the country the outside world finds difficult to deal with.
That split, too, began on March 21, 1935. A country insisted on its own name, and in doing so, it insisted on being taken seriously. It has been taken seriously ever since.