October 21 in History

Marcus Aurelius Valerius Maxentius was a Roman emperor from 306 until his death in 312. Despite ruling in Italy and North Africa, and having the recognition of the Senate in Rome, he was not recognized as a legitimate emperor by his fellow emperors.

Pope Conon (Greek: Κόνων, romanized: Konōn; died 21 September 687) was the bishop of Rome from 21 October 686 to his death on 21 September 687. He had been put forward as a compromise candidate, there being a conflict between the two factions resident in Rome — the military and the clerical. He consecrated the Irish missionary St Kilian and commissioned him to preach in Franconia.

Rodrigo Díaz de Vivar was a Castilian knight and ruler in medieval Spain. Fighting with both Christian and Muslim armies during his lifetime, he earned the Arabic honorific as-Sayyid, which would evolve into El Çid, and the Spanish honorific El Campeador. He was born in Vivar, a village near the city of Burgos.

The Sultanate of Rum, or Seljuk Sultanate of Rum, was a culturally Turco-Persian, Sunni Muslim state established over conquered Byzantine territories and peoples (Rum) of Anatolia by the Seljuk Turks following their entry into Anatolia after the Battle of Manzikert in 1071. The name Rum was a synonym for the medieval Roman Empire and its peoples, as it remains in modern Turkish. The name is derived from the Aramaic and Parthian names for ancient Rome, which had reached these languages via the Greek Ῥωμαῖοι. The Seljuk Turks used the name to refer to Anatolia. The Sultanate of Rum is considered to be the beginning of Turkish history in Anatolia.

The First Crusade (1096–1099) was the first of a series of religious wars, or Crusades, which were initiated, supported and at times directed by the Latin Church in the Middle Ages. Their aim was to return the Holy Land to Christian rule after its conquest by the Rashidun Caliphate in the 7th century. By the 11th century, although Jerusalem had then been ruled by Muslims for hundreds of years, the practices of the Seljuk rulers in the region began to threaten local Christian populations, pilgrimages from the West, and the Byzantine Empire itself. The earliest impetus for the First Crusade came in 1095 when Byzantine emperor Alexios I Komnenos sent ambassadors to the Council of Piacenza to request military support in the empire's conflict with the Seljuk-led Turks. This was followed later in the year by the Council of Clermont, at which Pope Urban II gave a speech supporting the Byzantine request and urging faithful Christians to undertake an armed pilgrimage to Jerusalem.

Al-Malik al-Mansur Abu al-Mudhaffar Imad al-Din Zengi bin Aq Sunqur al-Hajib bin Abdullah, also romanized as Zangi, Zengui, Zenki, and Zanki, was a Turkoman atabeg of the Seljuk Empire, who ruled Mosul, Aleppo, Hama, and, later, Edessa. He was the namesake and founder of the Zengid dynasty of atabegs.

Pope Gregory VIII (Latin: Gregorius VIII; c. 1100/1105 – 17 December 1187), born Alberto di Morra, was head of the Catholic Church and ruler of the Papal States for two months in 1187. Becoming Pope after a long diplomatic career as Apostolic Chancellor, he was notable in his brief reign for reconciling the Papacy with the estranged Holy Roman Empire and for initiating the Third Crusade.

Emperor Go-Kameyama (後亀山天皇, Go-Kameyama Tennō) (c. 1347 – May 10, 1424) was the 99th emperor of Japan, according to the traditional order of succession. He ruled from 1383 to October 21, 1392, becoming the last Emperor of the Southern Court. His personal name was Hironari (熙成). This 14th century sovereign was named after the 13th century Emperor Kameyama and go- (後), translates literally as "later"; and thus, he could be called the "Later Emperor Kameyama". The Japanese word "go" has also been translated to mean the "second one"; and in some older sources, this emperor may be identified as "Kameyama, the second" or as "Kameyama II".

Martin Luther ( LOO-thər; German: [ˈmaʁtiːn ˈlʊtɐ] ; 10 November 1483 – 18 February 1546) was a German priest, theologian, author, hymnwriter, professor, and former Augustinian friar. Luther was the seminal figure of the Protestant Reformation, and his theological beliefs form the basis of Lutheranism. He is considered one of the most influential figures in Western and Christian history. Born in Eisleben, Luther was ordained to the priesthood in 1507. He came to reject various teachings and practices of the Roman Catholic Church, in particular the view on indulgences and papal authority. Luther initiated an international debate on these in works like his Ninety-five Theses, which he authored in 1517. In 1520 Pope Leo X demanded that Luther renounce all of his writings, and when Luther refused to do so, excommunicated him in January 1521. Later that year the Holy Roman Emperor, Charles V, condemned Luther as an outlaw at the Diet of Worms. At the time of Luther's death in 1546, his excommunication was still in effect. Luther taught that justification is not earned by any human acts or intents or merit. He preached it instead is received only as the free gift of God's grace through the believer's faith in Jesus. Luther held that good works were a necessary fruit of living faith, part of the process of sanctification. Luther's theology challenged the authority and office of the pope and bishops by teaching that the Bible is the only source of divinely revealed knowledge on the Gospel. Those who identify with these, as well as Luther's wider teachings, are called Lutherans, although Luther insisted on Christian or Evangelical (German: evangelisch), as the only acceptable names for persons who professed Christ. Luther's translation of the Bible into German (1534) made the Bible vastly more accessible to the laity, which had a tremendous impact on both the Church and German culture. It fostered the development of a standard version of the German language, added several principles to the art of translation, and influenced the writing of an English translation, the Tyndale Bible. His hymns influenced the development of singing in Protestant churches. His marriage to Katharina von Bora, a former nun, set a model for the practice of clerical marriage, allowing Protestant clergy to marry. Luther expressed staunchly antisemitic views, calling for the expulsion of Jews and the burning of synagogues. In 1523, Luther wrote that Jesus Christ was born a Jew which discouraged mistreatment of the Jews and advocated their conversion by proving that the Old Testament could be shown to speak of Jesus Christ. However, as the Reformation grew, Luther began to lose hope in large-scale Jewish conversion to Christianity, and in the years his health deteriorated he grew more acerbic toward the Jews, writing against them with the kind of venom he had already unleashed on the Anabaptists, Zwingli, and the pope. These works also targeted Roman Catholics, Anabaptists, and nontrinitarian Christians. While Luther did not advocate the murder of Jews, some historians contend that his rhetoric encouraged antisemitism in Germany and the emergence, centuries later, of the Nazi Party.

João Álvares Fagundes (born c. 1460 – died 1522, Kingdom of Portugal) was an explorer and ship owner from Viana do Castelo in Northern Portugal. He organized several expeditions to Newfoundland and Nova Scotia around 1520–1521. Fagundes, together with his second captain Pero de Barcelos, and accompanied by colonists (mostly from the Azores and some from mainland Portugal), explored the islands of St Paul near Cape Breton, Sable Island, Penguin Island (now known as Funk Island), Burgeo, and Saint Pierre and Miquelon. He named the latter islands as the Eleven Thousand Virgins, in honor of Saint Ursula. King Manuel I of Portugal gave Fagundes exclusive rights and ownership of his discoveries on 13 March 1521. In 1607, Samuel de Champlain identified the remains of a large cross ("an old cross, all covered with moss, and almost wholly rotted away") at what is now Advocate Harbour, Nova Scotia on the Minas Basin. Some historians have attributed the cross to Fagundes, who is presumed to have visited the spot some eight decades earlier.

Tokugawa Ieyasu (born Matsudaira Takechiyo; January 31, 1543 – June 1, 1616) was a Japanese samurai, daimyo and the founder and first shogun of the Tokugawa shogunate of Japan, which ruled from 1603 until the Meiji Restoration in 1868. He was the third of the three "Great Unifiers" of Japan, along with his former lord Oda Nobunaga and fellow Oda subordinate Toyotomi Hideyoshi. The son of a minor daimyo, Ieyasu once lived as a hostage under daimyo Imagawa Yoshimoto on behalf of his father. He later succeeded as daimyo after his father's death, serving as ally, vassal, and general of the Oda clan, and building up his strength under Oda Nobunaga. After Oda Nobunaga's death, Ieyasu was briefly a rival of Toyotomi Hideyoshi, before declaring his allegiance to Toyotomi and fighting on his behalf. Under Toyotomi, Ieyasu was relocated to the Kanto plains in eastern Japan, away from the Toyotomi power base in Osaka. He built his castle in the fishing village of Edo (now Tokyo). He became the most powerful daimyo and the most senior officer under the Toyotomi regime. Ieyasu preserved his strength during Toyotomi's failed attempts to conquer Korea. After Hideyoshi's death and the Battle of Sekigahara, Ieyasu seized power in 1600. He received appointment as shōgun in 1603, and voluntarily resigned from his position in 1605, although he still held the de facto control of government until his death in 1616. He implemented a set of careful rules known as the bakuhan system. This system used precisely graded rewards and punishments to encourage (or compel) the daimyo and samurai to live in peace with each other under the Tokugawa shogunate. Following his death, his successors shifted the government to Edo in 1638 and enacted the sakoku policy of isolationism in 1639 which closed off Japan from the outside world for over 200 years (with some exceptions) until the Meiji era began in 1868.

Maarten Harpertszoon Tromp (23 April 1598 – 31 July 1653), also known as Maarten van Tromp, was an army general and admiral in the Dutch navy during much of the Eighty Years' War and throughout the First Anglo-Dutch War. Born in Brielle, the son of a ship's captain, Tromp spent much of his childhood at sea, during which time he was twice captured by pirates and sold into slavery. After regaining his freedom, he joined the Dutch navy and served with distinction, rising to the rank of lieutenant admiral in 1637 during the Eighty Years' War. Subsequently at the behest of Stadtholder Frederick Henry, Prince of Orange he accepted the command of the Dutch navy, which had fallen into a deplorable state due to incompetence and neglect. In 1639, through the deliberate use of line of battle tactics, he won a decisive victory over Antonio de Oquendo's Spanish fleet at the Battle of the Downs. The defeat all but marked the end of Spain's power at sea and ushered in an era of Dutch maritime supremacy. A skirmish between Tromp and English Admiral Robert Blake at Dover in 1652 led to the outbreak of the First Anglo-Dutch War. Temporary control of the English Channel following the Dutch victory at Dungeness was soon lost when Tromp suffered a significant defeat at the Gabbard in the face of superior English firepower. During the final battle of the war at Scheveningen in July 1653, Tromp was fatally wounded by an English sharpshooter. His death, a major blow to both the Dutch navy and the Orangist faction, solidified his public status as a naval hero. He was accorded a state funeral and interred in the Oude Kerk in Delft. An innovative tactician and a key figure in the rise of the Dutch Republic as a major power, Tromp was widely considered the best Dutch naval commander of his time as well as a folk hero.

Boston Harbor is a natural harbor and estuary of Massachusetts Bay, located adjacent to Boston, Massachusetts. It is home to the Port of Boston, a major shipping facility in the Northeastern United States.

The Napoleonic Wars (1803–1815) were a global series of conflicts fought by shared European coalitions against the French First Republic (1803–1804) under the First Consul followed by the First French Empire (1804–1815) under the Emperor of the French, Napoleon I. The wars originated in political forces arising from the French Revolution (1789–1799) and French Revolutionary Wars (1792–1802) and produced a period of French domination over continental Europe. The wars are categorised as seven conflicts, five named after the coalitions that fought Napoleon, plus two named for their respective theatres: the War of the Third Coalition, War of the Fourth Coalition, War of the Fifth Coalition, War of the Sixth Coalition, War of the Seventh Coalition, the Peninsular War, and the French invasion of Russia. The first stage of the wars broke out when Britain declared war on France on 18 May 1803. After minor campaigns, Britain allied with Austria, Russia, and minor powers, to form the Third Coalition in April 1805. Napoleon defeated the allied Russo-Austrian armies in the subsequent war which climaxed in French victories at Ulm and at Austerlitz, leading to the dissolution of the Holy Roman Empire and Austria being forced to make peace. Britain and Russia remained at war with France. Concerned about increasing French power, Prussia joined Britain and Russia in the Fourth Coalition, which resumed war in October 1806. Napoleon defeated the Prussians at Jena-Auerstedt and the Russians at Friedland, bringing an uneasy peace to the continent by July 1807, and again leaving Britain as France's sole major enemy. Britain was unable to dispute French dominance on the continent but obtained hegemony over the seas after victories including Trafalgar. Russia used the interim peace to resolve wars with the Ottomans, Swedes, and Iranians. Hoping to isolate and weaken Britain economically through his Continental System, Napoleon launched an invasion of Portugal, the only remaining British ally in continental Europe. After occupying Lisbon in November 1807, and with the bulk of French troops present in Spain, Napoleon seized the opportunity to turn against his former ally, depose the reigning Spanish royal family, and declare his brother, Joseph I as the King of Spain in 1808, much to the disapproval of the Spanish populace. Spain joined Britain and Portugal, with the three powers engaging France in the Peninsular War. The diversion of French armies to the large new Anglo-Spanish front led to Austria reentering the conflict and forming the Fifth Coalition in April 1809, composed of Austria, Spain, and Britain. Austria won the Battle of Aspern–Essling but was defeated at Wagram, forcing the imposition of a harsh peace in October 1809. Britain, Spain, and Portugal remained at war with France. Concurrently Russia, unwilling to bear the economic consequences of reduced trade, violated the Continental System, prompting Napoleon to launch an invasion in June 1812. The resulting campaign was costly for both sides, but ultimately ended in disaster for France and the near-destruction of Napoleon's Grande Armée. French forces retreated from Russia by December 1812 and began reconstituting their lost strength. Encouraged by the defeat, Austria, Prussia, and several minor powers joined Russia, Britain, and Spain in a Sixth Coalition and began a campaign against France. The Sixth Coalition defeated Napoleon at Leipzig in October 1813. The allies then invaded France on two fronts: the Russians, Austrians, and Prussians invaded France from the east, while the British, Spanish, and Portuguese invaded France from the west. Coalition troops captured Paris in March 1814, forced Napoleon to abdicate in April, exiled him to the island of Elba, and restored power to the Bourbons. Napoleon escaped exile in February 1815 and reassumed control of France for around one hundred days, igniting the eponymous conflict. The allies formed the Seventh Coalition, which defeated him at Waterloo in June 1815 and exiled him to Saint Helena, where he died in 1821. The wars had profound consequences on history. New methods of warfare were introduced, including mass conscription and guerrilla warfare. Politically, the wars greatly influenced Europe through the advancements in civil law brought about by the Napoleonic Code, which was largely retained where it was adopted, and the spread of nationalism and liberalism. Independence movements emerged in Spanish America as a direct consequence of the wars, leading to the decline of the Spanish and Portuguese Empires. France's defeat led to the rise of Britain as the world's foremost naval and economic power, a status it would hold for the remainder of the century. After the end of the Napoleonic Wars, the Congress of Vienna redrew Europe's borders and brought a relative peace to the continent, with no major great power conflicts until the Crimean War in 1853.

Portland cement is the most common type of cement in general use around the world as a basic ingredient of concrete, mortar, stucco, and non-specialty grout. It was developed from other types of hydraulic lime in England in the early 19th century by Joseph Aspdin, and is usually made from limestone. It is a fine powder, produced by heating limestone and clay minerals in a kiln to form clinker, and then grinding the clinker with the addition of several percent (often around 5%) gypsum. Several types of Portland cement are available. The most common, historically called ordinary Portland cement (OPC), is grey, but white Portland cement is also available. The cement was so named by Joseph Aspdin, who obtained a patent for it in 1824, because, once hardened, it resembled the fine, pale limestone known as Portland stone, quarried from the windswept cliffs of the Isle of Portland in Dorset. Portland stone was prized for centuries in British architecture and used in iconic structures such as St Paul's Cathedral and the British Museum. His son William Aspdin is regarded as the inventor of "modern" Portland cement due to his developments in the 1840s. The low cost and widespread availability of the limestone, shales, and other naturally occurring materials used in Portland cement make it a relatively cheap building material. At 4.4 billion tons manufactured (in 2023), Portland cement ranks third in the list (by mass) of manufactured materials, outranked only by sand and gravel. These three are combined, with water, to make the most manufactured material, concrete. This is Portland cement's most common use.

Florence Nightingale was an English social reformer, statistician and the founder of modern nursing. Nightingale came to prominence while serving as a manager and trainer of nurses during the Crimean War, in which she organised care for wounded soldiers at Constantinople. She significantly reduced death rates by improving hygiene and living standards. Nightingale gave nursing a favourable reputation and became an icon of Victorian culture, especially in the persona of "The Lady with the Lamp" making ward rounds for wounded soldiers at night.

The American Civil War (April 12, 1861 – May 26, 1865; also known by other names) was a civil war in the United States between the Union ("the North") and the Confederacy ("the South"), which was formed in 1861 by Southern states that had seceded from the Union to preserve slavery in the United States. The South saw slavery as threatened because of the election of Abraham Lincoln as president in 1860 and the growing abolitionist movement in the North. The war ended with a Union victory, dissolution of the Confederacy and the national abolition of slavery, freeing four million African Americans. Decades of controversy over slavery came to a head when Lincoln, a Republican who opposed slavery's expansion, won the 1860 presidential election. Seven slave states in the South responded to Lincoln's victory by seceding from the United States and forming the Confederate States. The Confederate States seized United States forts and other federal assets in the South. The war began on April 12, 1861, when the Confederate States bombarded Fort Sumter in South Carolina. A wave of enthusiasm for war swept over the North and South, as military recruitment soared. Four more Southern states seceded after the war began and, led by its president Jefferson Davis, the Confederacy comprised eleven states, containing a third of the US population. Four years of intense combat, mostly in the South, ensued. During 1861–1862 in the western theater, the Union made permanent gains, though in the eastern theater the conflict was inconclusive. The abolition of slavery became a Union war goal on January 1, 1863, when Lincoln issued the Emancipation Proclamation, which declared all slaves in rebel states to be free, applying to more than 3.5 million of the 4 million enslaved people in the country. To the west, the Union first destroyed the Confederate river navy by the summer of 1862, then much of its western armies, and seized New Orleans. The successful 1863 Union siege of Vicksburg split the Confederacy in two at the Mississippi River, while Confederate general Robert E. Lee's incursion north failed at the Battle of Gettysburg. Union general Ulysses S. Grant's western successes led Lincoln to promote him to command of all Union armies in 1864. Inflicting an ever-tightening naval Union blockade of Confederate ports, the Union army marshaled resources and the manpower to attack the Confederate States army from all directions. That led to the fall of Atlanta in 1864 to Union general William Tecumseh Sherman, followed by his March to the Sea, which culminated in his taking Savannah. The last significant battles raged around the ten-month siege of Petersburg, gateway to the Confederate capital of Richmond. The Confederates abandoned Richmond, and on April 9, 1865, Lee surrendered to Grant following the Battle of Appomattox Court House, setting in motion the end of the war. Lincoln lived to see this victory but was shot by an assassin on April 14, dying the next day. By the end of the war, much of the South's infrastructure had been destroyed. The Confederacy collapsed, the Thirteenth Amendment abolished slavery (except as punishment for a crime) and four million enslaved black people were freed. The war-torn nation then entered the Reconstruction era in an attempt to rebuild the country, reunite by bringing the former Confederate states back into the United States, and grant civil rights to freed black slaves. The war is one of the most extensively studied and written about episodes in the history of the United States, and it remains the subject of cultural and historiographical debate. Interest continues in the myth of the Lost Cause of the Confederacy. The war was among the first to use industrial warfare. Railroads, the electrical telegraph, steamships, the ironclad warship, and mass-produced weapons were widely used. The war left an estimated 700,000 soldiers dead, along with an undetermined number of civilian deaths, making it the deadliest in U.S. history. The technology and brutality of the Civil War foreshadowed the coming world wars.

The Medicine Lodge Treaty is the overall name for three treaties signed near Medicine Lodge, Kansas, between the Federal government of the United States and southern Plains Indian tribes in October 1867, intended to bring peace to the area by relocating the Native Americans to reservations in Indian Territory and away from European-American settlement. The treaty was negotiated after investigation by the Indian Peace Commission, which in its final report in 1868 concluded that the wars had been preventable. They determined that the United States government and its representatives, including the United States Congress, had contributed to the warfare on the Great Plains by failing to fulfill their legal obligations and to treat the Native Americans with honesty. The U.S. government and tribal chiefs met at a place traditional for Native American ceremonies, at their request. The first treaty was signed October 21, 1867, with the Kiowa and Comanche tribes. The second, with the Kiowa-Apache, was signed the same day. The third treaty was signed with the Southern Cheyenne and Arapaho on October 28. Under the Medicine Lodge Treaty, the tribes were assigned reservations of diminished size compared to territories defined in an 1865 treaty. The treaty tribes never ratified the treaty by vote of adult men, as it required. In addition, by changing allotment policy under the Dawes Act and authorizing sales under the Agreement with the Cheyenne and Arapaho (1890) and the Agreement with the Comanche, Kiowa and Apache (1892) signed with the Cherokee Commission, the Congress effectively further reduced their reservation territory. The Kiowa chief Lone Wolf filed suit against the government for fraud on behalf of the tribes in Lone Wolf v. Hitchcock. In 1903 the U.S. Supreme Court ruled against the tribes, determining that the Congress had "plenary power" and the political right to make such decisions. In the aftermath of that case, Congress acted unilaterally on land decisions related to other reservations as well. Because of the outstanding issues with the treaty and subsequent government actions, in the mid-20th century, the Kiowa, Arapaho and Comanche filed several suits for claims against the U.S. government. Over decades, they won substantial settlements of monetary compensation in the amount of tens of millions of dollars, although it took years for the cases to be resolved.

Thomas Alva Edison (February 11, 1847 – October 18, 1931) was an American inventor and businessman known for his work on the incandescent light bulb, the phonograph, electric power distribution and early motion pictures. The merger of the Edison General Electric Company and the competitor Thomson-Houston Electric Company resulted in the formation of General Electric. Edison registered 1,093 patents in the United States. Edison was born in Milan, Ohio, but grew up in Michigan with little formal schooling. He became deaf as a child and learned through books and tinkering. Edison began working at a young age; as a railroad telegrapher, he spent much of his time inventing improvements to telegraph systems. By the age of 22, he had sold a few of his early inventions and moved to New York City to focus on engineering. He had three children with his first wife, Mary, but Edison was neglectful. She died at 29 years old. Edison had troubled relationships with his children for the rest of his life. With the help of friends, the inventor attracted investment and grew his company. By the age of 29, he owned a telegraph recorder factory in Newark with over one hundred employees. Edison expanded, developing Menlo Park, now considered the first industrial research laboratory. Edison, known as "The Wizard of Menlo Park", drove his staff extremely hard and constantly worked himself and his associates to exhaustion. The inventor also drove up investment and publicity. He rose to international fame with the invention of the phonograph which took many years to turn into a commercial success. He later built a larger research lab in West Orange, New Jersey. In 1878, Edison began working on an electrical lighting system which he hoped would replace the common gas lamp. Going from electrical light bulb to the modern electric grid took decades of invention, investment, and influence. Edison and his colleagues had the opportunity to get enormously wealthy as they designed and built a nation of light bulbs, generators, and electric distribution systems. Competition with Westinghouse's AC system forced Edison to yield and resulted in the creation of General Electric. Edison simultaneously created a mining company, which was never profitable, and he nearly went bankrupt. As his role in the illumination business declined, he established a cement company and began work on a motion picture camera. The motion picture camera went from an invention to the first movie production studio. He traveled around the United States and Europe promoting his many innovations, during which he met Mina, his second wife. They had three children together, and Edison was again neglectful. During their adulthood, he began to take more interest in his sons and they eventually worked for him. Charles Edison took over his father's business when he died. In addition to acute health issues from handling toxic and radioactive chemicals during his various experiments, Thomas faced a lifelong battle against diabetes. He worked vigorously until his death. Following the success of the illumination business, he ran several companies which produced batteries, movies, musical records, and phenol. His last obsession was the search for domestic rubber production.

The Social Democratic Party of Switzerland, also called the Swiss Socialist Party, is a political party in Switzerland. The SP has had two representatives on the Federal Council since 1960 and received the second-highest number of votes in the 2023 Swiss federal election.

The World's Columbian Exposition, also known as the Chicago World's Fair, was a world's fair held in Chicago from May 1 to October 30, 1893, to celebrate the 400th anniversary of Christopher Columbus's arrival in the New World in 1492. The centerpiece of the fair, held in Jackson Park, was a large water pool representing the voyage that Columbus took to the New World. Chicago won the right to host the fair over several competing cities, including New York City, Washington, D.C., and St. Louis. The exposition was an influential social and cultural event and had a profound effect on American architecture, the arts, American industrial optimism, and Chicago's image.

The Capitulation of Tainan, on 21 October 1895, was the last act in the Japanese invasion of Taiwan. The capitulation ended the brief existence of the Republic of Formosa and inaugurated the era of Japanese colonial rule in Taiwan.

HMS Niobe was a ship of the Diadem class of protected cruisers in the Royal Navy. She served in the Boer War and was then given to Canada as the second ship of the newly created Naval Service of Canada as HMCS Niobe. The Naval Service of Canada became the Royal Canadian Navy in August 1911. The ship was nearly lost when she went aground off Cape Sable Island, Nova Scotia overnight 30–31 July 1911. Repairs were completed at the end of 1912 and the ship returned to service in late 1914. During the First World War, Niobe patrolled the approaches to the St. Lawrence River and then joined the Royal Navy's 4th Cruiser Squadron to patrol off New York City. The cruiser returned to Halifax, Nova Scotia on 17 July 1915 and never put to sea again. Niobe was paid off in September and served as a depot ship in Halifax. Damaged in the 1917 Halifax Explosion, she was sold for scrap and broken up in the 1920s.

The First Balkan War lasted from October 1912 to May 1913 and involved actions of the Balkan League (the Kingdoms of Bulgaria, Serbia, Greece and Montenegro) against the Ottoman Empire. The Balkan states' combined armies overcame the initially numerically inferior (significantly superior by the end of the conflict) and strategically disadvantaged Ottoman armies, achieving rapid success. The war was a comprehensive and unmitigated disaster for the Ottomans, who lost 83% of their European territories and 69% of their European population. As a result of the war, the League captured and partitioned almost all of the Ottoman Empire's remaining territories in Europe. Ensuing events also led to the creation of an independent Albania, which dissatisfied the Serbs. Bulgaria, meanwhile, was dissatisfied over the division of the spoils in Macedonia and attacked its former allies, Serbia and Greece, on 16 June 1913, which provoked the start of the Second Balkan War. During the war, many civilians were either killed or forced to flee their homes.

Warren Gamaliel Harding (November 2, 1865 – August 2, 1923) was the 29th president of the United States, serving from 1921 until his death in 1923. A member of the Republican Party, he was one of the most popular presidents at the time of his death. After that, a number of scandals were exposed that greatly damaged his reputation. Harding lived in rural Ohio all his life, except when political service took him elsewhere. As a young man, he bought The Marion Star and built it into a successful newspaper. Harding served in the Ohio State Senate from 1900 to 1904, and was lieutenant governor for two years. He was defeated for governor in 1910, but was elected to the United States Senate in 1914—the state's first direct election for that office. Harding ran for the Republican nomination for president in 1920, but was considered a long shot before the convention. When the leading candidates could not garner a majority, and the convention deadlocked, support for Harding increased, and he was nominated on the tenth ballot. He conducted a front porch campaign, remaining mostly in Marion and allowing people to come to him. He promised a return to normalcy of the pre–World War I period, and defeated Democratic nominee James M. Cox in a landslide, becoming the first sitting senator to be elected president. Harding appointed a number of respected figures to his cabinet, including Andrew Mellon at Treasury, Herbert Hoover at Commerce, and Charles Evans Hughes at the State Department. A major foreign policy achievement came with the Washington Naval Conference of 1921–1922, in which the world's major naval powers agreed on a naval limitations program that lasted a decade. Harding released political prisoners who had been arrested for their opposition to World War I. In 1923, he died of a heart attack in San Francisco while on a western tour, and was succeeded by Vice President Calvin Coolidge. The exposure of scandals after Harding's death, including Teapot Dome, as well as an extramarital affair with Nan Britton, eroded his popularity. His interior secretary, Albert B. Fall, and his attorney general, Harry Daugherty, were each later tried for corruption in office; Fall was convicted and Daugherty was not. These trials greatly damaged Harding's posthumous reputation. In historical rankings of U.S. presidents during the decades after his term in office, Harding was often rated among the worst. In the subsequent decades, some historians have begun to reassess Harding's record in office.

The Imperial Japanese Army (IJA) was the principal ground force of the Empire of Japan from 1871 to 1945. It played a central role in Japan's rapid modernization during the Meiji period. It also fought in numerous conflicts including the First Sino-Japanese War, Russo-Japanese War, World War I, Second Sino-Japanese War, World War II, and became a dominant force in Japanese politics. Initially formed from samurai domain armies that overthrew the Tokugawa Shogunate, it evolved after the Meiji Restoration into a powerful modern military influenced by French and German models, supported by its own air arm, the Imperial Japanese Army Air Service.

Ernest Miller Hemingway was an American novelist, short-story writer, and journalist. Known for an economical, understated style that influenced later 20th-century writers, he has been romanticized for his adventurous lifestyle and outspoken, blunt public image. Some of his seven novels, six short-story collections and two non-fiction works have become classics of American literature, and he was awarded the 1954 Nobel Prize in Literature.

World War II, or the Second World War, was a global conflict between two coalitions: the Allies and the Axis powers. Nearly all of the world's countries participated, with many engaging in total war on an unprecedented scale. World War II was the deadliest conflict in history, causing the deaths of 60 to 75 million people, a majority of whom were civilians. Millions died as a result of massacres, starvation, disease, and genocides, including the Holocaust. After the Allied victory, Germany, Austria, Japan, and Korea were occupied, and German and Japanese leaders were tried for war crimes.

The Provisional Government of Free India or, more simply, Azad Hind, was a short-lived Japanese-controlled provisional government in India. It was established in exile in Japanese-occupied Singapore during World War II in October 1943 and has been considered a puppet government of the Empire of Japan. It was a part of the political movement originating in the 1940s outside India with the purpose of allying with the Axis powers to defeat the British Raj. It was established by Indian nationalists in exile during the latter part of the World War II in Singapore with monetary, military and political assistance from Imperial Japan. Founded on 21 October 1943, the government was inspired by the concepts of Subhas Chandra Bose who was also the leader of the government and head of state. The government proclaimed authority over Indian civilian and military personnel in Southeast Asian British colonial territory and prospective authority over Indian territory to fall to the Japanese forces and the Indian National Army during the Japanese thrust towards India. The government of Azad Hind had its own currency, court and civil code, and in the eyes of some Indians, its existence gave a greater importance to the independence struggle against the British. Japan also handed over nominal authority of the Japanese-occupied Andaman and Nicobar Islands in 1943, though the government continued to be dependent on Japanese support. Immediately after the formation of the provisional government, Free India declared war against the Allied forces on the Indo-Burma Front. Its army, the Indian National Army (Azad Hind Fauj), went into action against the British Indian Army and the allied forces as part of the Imperial Japanese Army in the Imphal-Kohima sector. The INA had its first major engagement at the Battle of Imphal where, under the command of the Japanese Fifteenth Army, it breached the British defences in Kohima, reaching the salient of Moirang before suffering a catastrophic defeat as the Allied forces held, and Allied air dominance and compromised supply lines forced both the Japanese and the INA to retreat. The existence of Azad Hind was essentially coterminous with the existence of the Indian National Army. While the government itself continued until the civil administration of the Andaman Islands was returned to the jurisdiction of the British towards the end of the war, the limited power of Azad Hind was effectively ended with the surrender of the last major contingent of INA troops in Rangoon. The death of Bose is seen as the end of the entire Azad Hind Movement. The legacy of Azad Hind is, however, open to judgment. After the war, the Raj observed with alarm the transformation of the perception of Azad Hind from traitors and collaborators to liberators. After returning to India the veterans of the INA posed a difficult problem for the British government. The British feared that a public trial for treason on the part of the INA members might embolden anti-British sentiment and erupt into widespread protest and violence. The British Empire, which was seriously threatened by the INA, charged 300 INA officers with treason in the INA trials, but eventually backtracked in the face of opposition by the Congress.

HMAS Australia (I84/D84/C01) was a County-class heavy cruiser of the Royal Australian Navy (RAN). One of two Kent-subclass ships ordered for the RAN in 1924, Australia was laid down in Scotland in 1925, and entered service in 1928. Apart from an exchange deployment to the Mediterranean from 1934 to 1936, during which she became involved in the planned British response to the Abyssinia Crisis, Australia operated in local and South-West Pacific waters until World War II began.

The Nemmersdorf massacre was a civilian massacre perpetrated by Red Army soldiers in the late stages of World War II. Nemmersdorf was one of the first prewar ethnic German settlements to fall to the advancing Red Army during the war. On 21 October 1944, Soviet soldiers killed many German civilians as well as French and Belgian POWs.

The Battle of Aachen was a battle of World War II, fought by American and German forces in and around Aachen, Germany, between 12 September and 21 October 1944. The city had been incorporated into the Siegfried Line, the main defensive network on Germany's western border; the Allies had hoped to capture it quickly and advance into the industrialized Ruhr basin. Although most of Aachen's civilian population was evacuated before the battle began, much of the city was destroyed and both sides suffered heavy losses during the battle.

Legislative elections were held in France on 21 October 1945 to elect a Constituent Assembly to draft a constitution for a Fourth French Republic. A total of 522 seats were elected through proportional representation; women were allowed to vote for the first time.

The Battle of Yongyu, also known as the Battle of the Apple Orchard or the Battle of Yongju by the Australians who fought in it, took place between 21 and 22 October 1950 during the United Nations Command (UNC) offensive into North Korea against the Korean People's Army (KPA) that had invaded South Korea during the Korean War. The battle was fought between the 3rd Battalion, Royal Australian Regiment of the 27th British Commonwealth Brigade and the KPA 239th Regiment.

The Mau Mau rebellion (1952–1960), also known as the Mau Mau uprising or Kenya Emergency, was an armed conflict in the British Colony of Kenya between the Kenya Land and Freedom Army (KLFA) and the British colonial authorities. While the KLFA was primarily composed of Kikuyu, Meru, and Embu fighters, the movement also drew support from units of Kamba and Maasai. Groups such as the Luo and Kalenjin – who had led significant earlier resistance movements against colonial establishment, such as the Nandi Resistance (1890–1906) were largely not part of the KLFA's core structure. Instead, many from these communities served in the King's African Rifles (KAR), the colonial military force through which the British maintained internal security and quelled the uprising. The KLFA fought against the British Army and the local Kenya Regiment, which included European settlers and African loyalists.

The Solomon R. Guggenheim Museum, often referred to as The Guggenheim, is an art museum at 1071 Fifth Avenue between 88th and 89th Streets on the Upper East Side of Manhattan in New York City. It hosts a permanent collection of Impressionist, Post-Impressionist, early Modern and contemporary art and also features special exhibitions throughout the year. It was established by the Solomon R. Guggenheim Foundation in 1939 as the Museum of Non-Objective Painting, under the guidance of its first director, Hilla von Rebay. The museum adopted its current name in 1952, three years after the death of its founder Solomon R. Guggenheim. It continues to be operated and owned by the Solomon R. Guggenheim Foundation.

Dwight David "Ike" Eisenhower was the 34th president of the United States, serving from 1953 to 1961. In his previous military career, he commanded the Allied Expeditionary Force during World War II, including in Operation Torch in North Africa and Operation Overlord on D-Day in Normandy. For his distinguished service in the U.S. Army, Eisenhower was honored with the five-star rank of General of the Army.

Comet Ikeya–Seki, formally designated C/1965 S1, 1965 VIII, and 1965f, was a long-period comet discovered independently by Kaoru Ikeya and Tsutomu Seki. First observed as a faint telescopic object on 18 September 1965, the first calculations of its orbit suggested that on October 21, it would pass just 450,000 km (280,000 mi) above the Sun's surface, and would probably become extremely bright.

The Aberfan disaster was the catastrophic collapse of a colliery spoil tip on 21 October 1966. The tip had been created on a mountain slope above the Welsh village of Aberfan, near Merthyr Tydfil, and overlaid a natural spring. Heavy rain led to a build-up of water within the tip which caused it to suddenly slide downhill as a slurry, killing 116 children and 28 adults as it engulfed Pantglas Junior School and a row of houses. The tip was the responsibility of the National Coal Board (NCB), and the subsequent inquiry placed the blame for the disaster on the organisation and nine named employees.

The Clarkston explosion was a disaster that occurred on 21 October 1971 in a row of shops on the main street of Clarkston, East Renfrewshire, Scotland. Sources from the time state the death toll as 21, whilst modern sources state 22.

John Frederick Dryer is an American actor, radio host, and former professional football player who played as a defensive end in the National Football League (NFL) for 13 years with the New York Giants and Los Angeles Rams, participating in 176 games and recorded 103 career sacks starting in 1969 until his retirement in 1981, and is the only NFL player to score two safeties in one game. Following his retirement from football, Dryer had a successful career as a film and television actor, notably starring as the titular character Detective Sgt. Rick Hunter in the NBC police drama series Hunter, with his height of 6 ft 6 in (1.98 m) and physique proving useful for action roles.

Frederick Valentich was an Australian pilot who disappeared while on a 125-nautical-mile (232 km) flight in a Cessna 182L light aircraft, registered VH-DSJ, over Bass Strait. On the evening of Saturday 21 October 1978, twenty-year-old Valentich informed Melbourne air traffic control that he was being accompanied by an aircraft about 1,000 feet (300 m) above him and that his engine had begun running roughly, before finally reporting: "It's not an aircraft".

Moshe Dayan was an Israeli military leader and politician. As commander of the Jerusalem front in the 1948 Arab–Israeli War, Chief of the General Staff of the Israel Defense Forces (1953–1958) during the 1956 Sinai War, and as Defense Minister during the Six-Day War in 1967, he became a worldwide fighting symbol of the state of Israel.

Andreas Georgiou Papandreou was a Greek academic and economist who was prime minister of Greece from 1981 to 1989 and again from 1993 to 1996. He founded PASOK, the Panhellenic Socialist Movement.

The metre is the base unit of length in the International System of Units (SI). Since 2019, the metre has been defined as the length of the path travelled by light in vacuum during a time interval of ⁠1/299792458⁠ of a second, where the second is defined by a hyperfine transition frequency of caesium.

Andreas Nikolaus "Niki" Lauda was an Austrian racing driver, motorsport executive, and aviation entrepreneur, who competed in Formula One from 1971 to 1979 and from 1982 to 1985. Lauda won three Formula One World Drivers' Championship titles and—at the time of his retirement—held the record for most podium finishes (54); he won 25 Grands Prix across 13 seasons, and remains the only driver to have won a World Drivers' Championship with both Ferrari and McLaren.

The Lebanon hostage crisis was the kidnapping in Lebanon of 104 foreign hostages between 1982 and 1992, when the Lebanese Civil War was at its height. The hostages were mostly Americans and Western Europeans, but 21 national origins were represented. At least eight hostages died in captivity; some were murdered, while others died from lack of medical attention. During the fifteen years of the civil war, an estimated 17,000 people disappeared after being abducted.

The Jaffna hospital massacre occurred on October 21 and 22, 1987, during the Sri Lankan Civil War, when troops of the Indian Peace Keeping Force entered the premises of the Jaffna Teaching Hospital in Jaffna, Sri Lanka, an island nation in South Asia, and killed between 60 and 70 patients and staff. The rebel Liberation Tigers of Tamil Eelam, the government of Sri Lanka, and independent observers such as the University Teachers for Human Rights and others have called it a massacre of civilians.

Honduras, officially the Republic of Honduras, is a country in Central America. It is bordered to the west by Guatemala, to the southwest by El Salvador, to the southeast by Nicaragua, to the south by the Pacific Ocean at the Gulf of Fonseca, and to the north by the Gulf of Honduras, a large inlet of the Caribbean Sea. Its capital and largest city is Tegucigalpa.

The Agreed Framework between the United States of America and the Democratic People's Republic of Korea (Korean: 북미제네바기본합의서) was signed on 21 October 1994, between North Korea (DPRK) and the United States. The objective of the agreement was the freezing and replacement of North Korea's indigenous nuclear power plant program with more nuclear proliferation resistant light water reactor power plants, and the step-by-step normalization of relations between the U.S. and the DPRK. Implementation of the agreement was troubled from the start, but its key elements were being implemented until it effectively broke down in 2003.

The Seongsu Bridge disaster was a deadly bridge collapse that occurred on the morning of October 21, 1994 in Seoul, South Korea. A section of the upper truss of the Seongsu Bridge collapsed onto the Han River, killing 32 people and injuring another 17. A combination of faulty welding, rusted extension hinges, and insufficient maintenance resulted in the structural failure of the bridge.

Eris is the most massive and second-largest-known dwarf planet in the Solar System. It is a trans-Neptunian object (TNO) in the scattered disk and has a high-eccentricity orbit. Eris was discovered in January 2005 by a Palomar Observatory–based team led by Mike Brown and verified later that year. It was named in September 2006 after the Greco-Roman goddess of strife and discord. Eris is the ninth-most massive known object orbiting the Sun and the sixteenth-most massive in the Solar System. It is also the largest-known object in the Solar System that has not been visited by a spacecraft. Eris has been measured at 2,326 ± 12 kilometres (1,445 ± 7 mi) in diameter; its mass is 0.28% that of the Earth and 27% greater than that of Pluto, although Pluto is slightly larger by volume. Both Eris and Pluto have a surface area that is comparable to that of Russia or South America.

Kimi-Matias Räikkönen is a Finnish racing and rally driver who competed in Formula One between 2001 and 2021, and the World Rally Championship from 2009 to 2011. Nicknamed "the Iceman", Räikkönen won the Formula One World Drivers' Championship in 2007 with Ferrari, and won 21 Grands Prix across 19 seasons.

The Iraq War, also referred to as the Second Gulf War, was a protracted armed conflict in Iraq from 2003 to 2011. It began in March 2003 with the invasion by a United States–led coalition, which resulted in the overthrow of the Ba'athist government of Saddam Hussein. During the US occupation of Iraq, the conflict persisted as an insurgency that arose against coalition forces and the newly established Iraqi government. US forces were officially withdrawn in 2011. In 2014, the US became re-engaged in Iraq, leading a new coalition under Combined Joint Task Force – Operation Inherent Resolve, as the conflict evolved into the ongoing Islamic State insurgency.

On 21 October 2018, a passenger train derailed in Yilan County, Taiwan, killing 18 people and injuring 187. At the time, it was Taiwan's deadliest rail accident since a collision near Miaoli in 1991 that killed 30 people. The Taiwan Transportation Safety Board titled this rail accident of "TRA's Train No. 6432 at Xinma Station".

The Democratic Republic of the Congo (DRC), also known as the DR Congo, Congo-Kinshasa, or simply the Congo, and formerly named Zaire, is a country in Central Africa. By land area, it is the second-largest country in Africa and the eleventh-largest in the world. With a population of about 124 million people, the Democratic Republic of the Congo is the fourth-most populous country in Africa and the most populous Francophone country in the world. French is the official and most widely spoken language. There are over 200 indigenous languages, of which Lingala is the most widely spoken. The capital, largest city, and economic center is Kinshasa. The DRC is bordered by the Republic of the Congo, the Cabinda exclave of Angola, and the South Atlantic Ocean to the west; the Central African Republic and South Sudan to the north; Uganda, Rwanda, Burundi, and Tanzania to the east; and Zambia and Angola to the south. Centered on the Congo Basin, most of the DRC's terrain is covered by dense rainforests and is crossed by many rivers. The east and southeast are mountainous.

Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the second-largest country by total area, with the longest coastline of any country. Its border with the United States is the longest international land border. The country is characterized by a wide range of both meteorologic and geological regions. With a population of over 41 million, it has widely varying population densities, with the majority residing in its urban areas and large areas being sparsely populated. Its capital is Ottawa and its three largest metropolitan areas are Toronto, Montreal, and Vancouver.