March 18

The Roman Senate proclaims Caligula emperor after annulling the will of his predecessor Tiberius.

Following the death of Emperor Tiberius, the Roman Senate proclaimed his 24-year-old great-nephew Gaius, nicknamed Caligula, as emperor, annulling Tiberius's will that would have shared power with another heir. Caligula's initially popular reign later descended into infamous cruelty and erratic behavior before his assassination four years later.

The Roman Senate proclaimed Caligula emperor following the death of his great-uncle Tiberius.

Caligula, born Gaius Julius Caesar Germanicus, was the popular young son of the beloved general Germanicus and initially enjoyed enormous public support. His reign began with a wave of goodwill and reforms, but he soon became notorious for extravagance, cruelty, and increasingly erratic behaviour, and was assassinated by his own guard within four years.

Jacques de Molay, the last Grand Master of the Knights Templar, is burned at the stake in Paris.

Jacques de Molay, the final Grand Master of the Knights Templar, was burned at the stake in Paris on charges of heresy after years of imprisonment and torture under King Philip IV of France, who sought to seize the order's wealth. His death effectively ended the once-powerful medieval military order.

The Powhatan Confederacy launched a surprise attack on English settlements in Virginia, beginning the Third Anglo-Powhatan War.

Led by the elderly chief Opechancanough, Powhatan warriors killed several hundred English colonists in a coordinated assault reminiscent of the 1622 uprising. The two-year conflict that followed ended in decisive defeat for the Powhatan Confederacy, whose remaining people were confined to reservations under English colonial authority, effectively ending organized Native resistance in the Virginia colony.

The British Parliament repeals the unpopular Stamp Act, easing tensions with the American colonies.

The British Parliament repealed the 1765 Stamp Act, which had imposed direct taxes on printed materials in the American colonies and sparked fierce colonial resistance. While celebrated in the colonies, Parliament simultaneously passed the Declaratory Act asserting its right to legislate for the colonies, setting the stage for future conflict.

The British Parliament repealed the Stamp Act, withdrawing the direct tax on American colonists that had provoked fierce resistance.

Passed the previous year to help fund British troops stationed in North America, the Stamp Act required colonists to pay for a physical stamp on legal documents, newspapers, and other paper goods. Widespread boycotts and protests, including the Stamp Act Congress, forced Parliament's hand. The same day, however, Parliament passed the Declaratory Act asserting its right to tax the colonies in the future, planting seeds for further conflict.

Six farm labourers from Tolpuddle, Dorset, were sentenced to penal transportation to Australia for forming an early agricultural trade union.

The men, later known as the Tolpuddle Martyrs, had sworn a secret oath to form a friendly society protecting labourers' wages, an act deemed illegal under obscure legislation aimed at naval mutinies. Public outcry over their harsh seven-year transportation sentences sparked mass protests and petitions, and the men were eventually pardoned and returned home. The case became a founding legend of the British trade union movement.

Parisians rise up and establish the revolutionary Paris Commune, which briefly governed the city.

Parisians, angered by the national government's attempt to seize the National Guard's cannons and by the hardships of the recent siege by Prussia, rose in revolt and established the Paris Commune, a radical socialist government that controlled the city for about two months before being violently suppressed.

Parisian workers and National Guardsmen seized control of the city, establishing the revolutionary Paris Commune.

The uprising followed France's defeat in the Franco-Prussian War and resentment at the conservative national government's peace terms. The Commune governed Paris for just over two months, implementing radical social reforms, before French government troops brutally suppressed it during the bloody "Semaine sanglante," killing thousands of Communards. The episode became a touchstone for later socialist and communist movements.

An Allied naval assault on the Dardanelles fails disastrously, with three battleships sunk, during World War I.

British and French warships attempted to force passage through the Dardanelles strait to threaten Constantinople but struck a minefield, losing three battleships and suffering heavy damage to others. The costly failure led Allied commanders to instead plan the ill-fated land invasion at Gallipoli.

British and French battleships attempting to force the Dardanelles strait were sunk or crippled by Ottoman mines, a major setback in the Gallipoli campaign.

An Allied fleet including the British battleships HMS Irresistible and HMS Ocean tried to smash through Ottoman defences to open a sea route to Constantinople. Undetected minefields sank both British ships along with the French battleship Bouvet, killing hundreds of sailors. The failure convinced Allied commanders that naval power alone could not defeat the straits' defences, leading directly to the disastrous land invasion at Gallipoli weeks later.

Mohandas Gandhi was sentenced to six years' imprisonment by a British colonial court in India on charges of sedition.

Gandhi had been arrested after publishing articles urging non-cooperation with British rule following violence at Chauri Chaura. At his trial in Ahmedabad he pleaded guilty and used the courtroom to indict British rule in India as a system of exploitation, in a statement that became one of the most famous speeches of the independence movement. He was released early in 1924 after an appendicitis operation.

Mexico nationalizes its foreign-owned oil industry, establishing the state company that became Pemex.

President Lazaro Cardenas signed a decree nationalizing Mexico's foreign-owned oil companies after a bitter labor dispute, expropriating British and American holdings and creating the state-run company Pemex. The move, still celebrated annually as a milestone of Mexican economic sovereignty, prompted a temporary international boycott of Mexican oil by the affected foreign corporations and their governments.

Adolf Hitler and Benito Mussolini meet at the Brenner Pass, cementing their wartime alliance.

Adolf Hitler met Benito Mussolini at the Brenner Pass on the Italian-Austrian border, seeking to secure Italian cooperation and passage of German troops through Italian territory as World War II expanded. The meeting reinforced the Axis alliance ahead of Germany's invasions later that year.

France and Algerian nationalists sign the Evian Accords, agreeing to end the Algerian War of Independence.

French President Charles de Gaulle's government and representatives of Algeria's National Liberation Front signed the Evian Accords, agreeing to a ceasefire and a referendum on Algerian self-determination. The agreement effectively ended the brutal eight-year Algerian War of Independence, though a formal ceasefire took effect the next day.

Soviet cosmonaut Alexei Leonov becomes the first person to walk in space.

Soviet cosmonaut Alexei Leonov exited his Voskhod 2 spacecraft tethered by a cable, becoming the first human to walk in space. His spacesuit swelled in the vacuum, nearly preventing his return to the capsule, in a harrowing episode not disclosed publicly until decades later.

Soviet cosmonaut Alexei Leonov became the first person to walk in space, exiting his Voskhod 2 capsule for just over twelve minutes.

Leonov's spacesuit ballooned dangerously in the vacuum of space, forcing him to bleed air from the suit to squeeze back through the airlock, a near-fatal complication concealed from the public for decades. The feat gave the Soviet Union another high-profile victory in the Space Race, just weeks before American astronaut Ed White performed the first American spacewalk that June.

The supertanker Torrey Canyon ran aground off the coast of Cornwall, causing Britain's worst oil spill to that date.

The Liberian-registered tanker spilled roughly 120,000 tonnes of crude oil into the English Channel, fouling beaches in Cornwall and across the water in France. The Royal Air Force and Navy bombed the wreck days later in an attempt to burn off the remaining oil, an operation of limited success. The disaster exposed the inadequacy of existing spill-response measures and spurred new international maritime pollution regulations.

Russia and Crimean officials sign a treaty formalizing Russia's annexation of Crimea, a move most of the world refused to recognize.

Russian President Vladimir Putin signed a treaty with Crimean officials formalizing the peninsula's annexation from Ukraine, following a disputed referendum held under Russian military presence. The international community broadly condemned the annexation as illegal, imposing sanctions that strained relations between Russia and the West for years.

Russia and representatives of Crimea signed a treaty formally annexing the Ukrainian peninsula following a disputed referendum.

The signing came days after a referendum on joining Russia that was held under military occupation and rejected as illegitimate by Ukraine and most of the international community. The annexation, Europe's first forcible seizure of territory since World War II, triggered Western sanctions against Russia and precipitated years of conflict in eastern Ukraine that escalated into full-scale war in 2022.