August 24 in History

A column of superheated gas and rock shot 33 kilometers into the sky above the Bay of Naples on August 24, 79 AD, as Mount Vesuvius tore itself apart in one of the deadliest volcanic eruptions in recorded history. Below, the Roman cities of Pompeii, Herculaneum, and Stabiae had roughly eighteen hours before they ceased to exist. Vesuvius had been rumbling for days. Small earthquakes rattled the region starting on August 20, but the residents of Pompeii, a prosperous trading city of roughly 11,000 people, were accustomed to tremors. A major earthquake had damaged the city in 62 AD, and reconstruction was still underway seventeen years later. Nobody recognized the shaking as a warning that the mountain above them was about to explode. When the eruption began around midday, it initially produced a rain of pumice stones that accumulated at a rate of about six inches per hour on Pompeii's rooftops. Many residents fled immediately. Others sheltered indoors, waiting for the bombardment to stop. The pumice phase lasted roughly twelve hours. Then, beginning around midnight, the eruption's character changed catastrophically. The column of ash and gas collapsed, sending pyroclastic surges racing down the mountainside at speeds exceeding 100 kilometers per hour and temperatures above 300 degrees Celsius. Herculaneum, closer to the volcano and directly downslope, was buried under 20 meters of volcanic material. The surges reached Pompeii by early morning, killing anyone still in the city almost instantly. Pliny the Elder, the famed naturalist and naval commander, died attempting a rescue mission across the bay. His nephew, Pliny the Younger, watched from Misenum and later wrote two letters describing the disaster that remain the earliest detailed eyewitness account of a volcanic eruption. Pompeii lay buried under four to six meters of ash for nearly 1,700 years until excavations began in 1748. The ash preserved buildings, frescoes, graffiti, food, and the contorted forms of the dead in extraordinary detail, giving modern archaeologists an unparalleled snapshot of Roman daily life frozen at the moment of its destruction.

Church bells rang across Paris before dawn on August 24, 1572, and the killing began. On the orders of King Charles IX, Catholic mobs systematically hunted down Huguenot Protestants who had gathered in the capital for a royal wedding. Over the next three days in Paris, and then for weeks across France, between 5,000 and 30,000 Huguenots were slaughtered in the worst mass killing of the French Wars of Religion. The massacre was triggered by a botched assassination. Two days earlier, an assassin had wounded Admiral Gaspard de Coligny, the Huguenot military and political leader who had been gaining influence over the young king. Coligny survived, and Huguenot nobles in Paris demanded justice. Catherine de Medici, the king's mother, feared a Protestant uprising and persuaded Charles to authorize a preemptive strike against Huguenot leaders gathered for the marriage of the Protestant Henry of Navarre to the king's sister Margaret. The wedding had been intended to heal the religious divide. Instead, it became the trap. Soldiers killed Coligny in his bed, threw his body from a window, and dumped it in the Seine. Royal troops then fanned out through Paris, marking Huguenot homes with crosses. Catholic mobs joined the killing, murdering men, women, and children. Bodies choked the rivers. The violence spread to at least a dozen provincial cities over the following weeks, with local authorities and Catholic populations carrying out their own massacres. Entire Huguenot communities were wiped out. Pope Gregory XIII reportedly celebrated with a Te Deum mass and commissioned a commemorative medal. The massacre radicalized both sides. Protestant political theorists developed early arguments for the right to resist tyrannical rulers, ideas that would influence revolutions centuries later. Henry of Navarre, forced to convert to Catholicism to save his life, eventually inherited the throne as Henry IV and issued the Edict of Nantes in 1598, granting Protestants limited religious freedom. The St. Bartholomew's Day Massacre became a defining moment in European religious history and a warning about what happens when states weaponize sectarian hatred.

Flames lit up the night sky over Washington, D.C., on August 24, 1814, as British soldiers put torches to the White House, the Capitol, the Treasury, and nearly every other public building in the American capital. The Burning of Washington remains the only time since the American Revolution that a foreign power has captured and occupied the capital of the United States. The attack came during the War of 1812, a conflict often overshadowed by the Napoleonic Wars raging in Europe. With Napoleon defeated and exiled to Elba in April 1814, Britain could redirect experienced veterans to the American theater. Rear Admiral George Cockburn and Major General Robert Ross landed 4,500 battle-hardened troops at Benedict, Maryland, and marched northwest toward Washington. President James Madison and Secretary of State James Monroe personally scouted the British advance. The American defense, roughly 7,000 militia and regulars hastily assembled at Bladensburg, collapsed after a brief engagement. The militia broke and ran so quickly that the battle was later nicknamed "the Bladensburg Races." Madison fled the capital. First Lady Dolley Madison famously stayed behind long enough to save Gilbert Stuart's full-length portrait of George Washington before escaping by carriage. British troops ate a dinner that had been prepared for the president at the White House before setting it ablaze. The Capitol, still under construction, burned so intensely that its interior was gutted. A violent thunderstorm the following day may have helped extinguish some fires and reportedly spawned a tornado that killed more British soldiers than the Battle of Bladensburg had. The British withdrew after less than 26 hours, but the psychological damage was enormous. The destruction galvanized American resistance and contributed to Andrew Jackson's decisive victory at New Orleans five months later. The White House was rebuilt with its iconic white-painted exterior, and the Capitol was reconstructed over the following decade. The burning became a rallying point for American nationalism and a reminder that the young republic's survival had never been guaranteed.

After a week of contentious debate in Prague, 424 astronomers voted on August 24, 2006, to strip Pluto of the planetary status it had held since Clyde Tombaugh discovered it in 1930. The International Astronomical Union's decision reduced the solar system from nine planets to eight and provoked a public backlash that far exceeded anything the astronomers anticipated. The crisis had been building since the 1990s, when researchers began discovering other icy bodies in the Kuiper Belt beyond Neptune's orbit. Several rivaled Pluto in size. The discovery of Eris in 2005, which appeared to be slightly larger than Pluto, forced the question: either Eris and dozens of similar objects were planets too, or Pluto was not. The IAU convened a committee to draft a definition, but the initial proposal, which would have expanded the planetary count to twelve, proved deeply unpopular among astronomers who studied planetary dynamics. The final definition established three criteria: a planet must orbit the Sun, have enough mass for gravity to pull it into a roughly spherical shape, and have "cleared the neighborhood" around its orbit of other debris. Pluto met the first two conditions but failed the third. Its orbit overlaps with Neptune's and crosses through a zone crowded with thousands of other Kuiper Belt objects. Pluto was reclassified as a "dwarf planet," a new category that satisfied almost nobody. Public reaction was fierce and immediate. Schoolchildren wrote protest letters. The New Mexico state legislature passed a resolution declaring that Pluto would always be a planet while in New Mexico's skies. NASA's New Horizons spacecraft, already en route to Pluto when the vote happened, arrived in 2015 and revealed a geologically complex world with nitrogen glaciers, mountain ranges of water ice, and a thin atmosphere. The flyby reignited the debate, but the IAU definition stands. Pluto remains the most famous dwarf planet in a solar system that officially has eight.

King John of England married the twelve-year-old Isabella of Angouleme in Bordeaux Cathedral on August 24, 1200, in a union driven as much by lust and territorial ambition as by diplomatic calculation. The marriage enraged the French nobleman to whom Isabella was already betrothed and set in motion a chain of feudal disputes that cost John nearly all of England's continental possessions. Isabella had been promised to Hugh IX of Lusignan, a powerful lord in Aquitaine whose family controlled strategically important territories in western France. John, who had recently divorced his first wife, was reportedly captivated by Isabella's beauty during a visit to her father's court. He married her without attempting to compensate or even properly notify the Lusignans. Hugh appealed to their mutual overlord for the French territories: King Philip II of France. Philip summoned John to appear before his court as Duke of Aquitaine to answer the Lusignan complaint. When John refused, Philip declared his French fiefs forfeit and launched an invasion. By 1204, Normandy, Anjou, Maine, and most of Aquitaine had fallen to the French crown. England lost territories the Norman and Angevin kings had held for over a century. The disaster was not solely caused by the marriage, but John's impulsive seizure of another lord's betrothed gave Philip the legal pretext he needed to strike. The loss of continental lands had enormous consequences for English history. John's desperate attempts to fund a reconquest led to heavy taxation and baronial resentment that culminated in the Magna Carta of 1215, the foundational document of English constitutional law. Isabella, for her part, outlived John by nearly three decades. After his death in 1216 she returned to France, married Hugh X of Lusignan (the son of her original betrothed), and wielded political influence in Aquitaine until she retired to Fontevraud Abbey. Her marriage to John had been the spark that reshaped the medieval balance of power between England and France.