Historical Events on this Day in History - per Wikipedia

May 21

• 293 – Roman Emperors Diocletian and Maximian appoint Galerius as Caesar to Diocletian, beginning the period of four rulers known as the Tetrarchy.
• 878 – Syracuse, Italy is captured by the Muslim sultan of Sicily.
• 879 – Pope John VIII gives blessings to duke Branimir and to Croatian people, considered to be international recognition of the Croatian state.
• 996 – Sixteen-year-old Otto III is crowned Holy Roman Emperor.
• 1502 – The island of Saint Helena is discovered by the Portuguese explorer João da Nova.
• 1554 – A royal Charter is granted to Derby School in Derby, England.
• 1674 – The nobility elect John Sobieski King of Poland and Grand Duke of Lithuania.
• 1725 – The Order of St. Alexander Nevsky is instituted in Russia by Empress Catherine I. It would later be discontinued and then reinstated by the Soviet government in 1942 as the Order of Alexander Nevsky.
• 1758 – Mary Campbell is abducted from her home in Pennsylvania by Lenape during the French and Indian War.
• 1809 – The first day of the Battle of Aspern-Essling between the Austrian army led by Archduke Charles and the French army led by Napoleon I of France sees the French attack across the Danube held.
• 1851 – Slavery is abolished in Colombia, South America.
• 1856 – Lawrence, Kansas is captured and burned by pro-slavery forces.
• 1863 – American Civil War: The Union Army succeeds in closing off the last escape route from Port Hudson, Louisiana, in preparation for the coming siege.
• 1863 – Organization of the Seventh-day Adventist Church in Battle Creek, Michigan.
• 1864 – Russia declares an end to the Russian-Circassian War and many Circassians are forced into exile. The day is designated the Circassian Day of Mourning.
• 1871 – French troops invade the Paris Commune and engage its residents in street fighting. By the close of "Bloody Week" some 20,000 communards have been killed and 38,000 arrested.
• 1871 – Opening of the first rack railway in Europe, the Rigi-Bahnen on Mount Rigi.
• 1879 – War of the Pacific: Two Chilean ships blocking the harbor of Iquique (then belonging to Peru) battle two Peruvian vessels in the Battle of Iquique.
• 1881 – The American Red Cross is established by Clara Barton.
• 1894 – The Manchester Ship Canal in England is officially opened by Queen Victoria, who knights its designer Sir Edward Leader Williams.
• 1904 – The Fédération Internationale de Football Association (FIFA) is founded in Paris.
• 1911 – Mexican President Porfirio Díaz and the revolutionary Francisco Madero sign the Treaty of Ciudad Juárez to put an end to the fighting between the forces of both men, and thus concluding the initial phase of the Mexican Revolution.
• 1917 – The Commonwealth War Graves Commission is established through Royal Charter to mark, record and maintain the graves and places of commemoration of Commonwealth of Nations military forces.
• 1917 – The Great Atlanta fire of 1917.
• 1924 – University of Chicago students Richard Loeb and Nathan Leopold, Jr. murder 14-year-old Bobby Franks in a "thrill killing".
• 1927 – Charles Lindbergh touches down at Le Bourget Field in Paris, completing the world's first solo nonstop flight across the Atlantic Ocean.
• 1932 – Bad weather forces Amelia Earhart to land in a pasture in Derry, Northern Ireland, and she thereby becomes the first woman to fly solo across the Atlantic Ocean.
• 1934 – Oskaloosa, Iowa, becomes the first municipality in the United States to fingerprint all of its citizens.
• 1936 – Sada Abe is arrested after wandering the streets of Tokyo for days with her dead lover's severed genitals in her hand. Her story soon becomes one of Japan's most notorious scandals.
• 1937 – A Soviet station becomes the first scientific research settlement to operate on the drift ice of the Arctic Ocean.
• 1939 – The Canadian National War Memorial is unveiled by King George VI and Queen Elizabeth in Ottawa.
• 1946 – Physicist Louis Slotin is fatally irradiated in a criticality incident during an experiment with the Demon core at Los Alamos National Laboratory.
• 1951 – The opening of the Ninth Street Show, otherwise known as the 9th Street Art Exhibition – a gathering of a number of notable artists, and the stepping-out of the post war New York avant-garde, collectively known as the New York School.
• 1961 – American civil rights movement: Alabama Governor John Malcolm Patterson declares martial law in an attempt to restore order after race riots break out.
• 1966 – The Ulster Volunteer Force declares war on the Irish Republican Army in Northern Ireland.
• 1969 – Civil unrest in Rosario, Argentina, known as Rosariazo, following the death of a 15-year-old student.
• 1972 – Michelangelo's Pietà in St. Peter's Basilica in Rome is damaged by a vandal, the mentally disturbed Hungarian geologist Laszlo Toth.
• 1979 – White Night riots in San Francisco following the manslaughter conviction of Dan White for the assassinations of George Moscone and Harvey Milk.
• 1981 – Irish Republican hunger strikers Raymond McCreesh and Patsy O’Hara die on hunger strike in Maze prison.
• 1982 – Falklands War: British amphibious assault during Operation Sutton lead to the Battle of San Carlos.
• 1990 – Democratic Republic of Yemen and North Yemen agree to merge into the Republic of Yemen.
• 1991 – Former Indian prime minister Rajiv Gandhi is assassinated by a female suicide bomber near Madras.
• 1991 – Mengistu Haile Mariam, president of the People's Democratic Republic of Ethiopia, flees Ethiopia, effectively bringing the Ethiopian Civil War to an end.
• 1994 – The Democratic Republic of Yemen unsuccessful attempts to secede from Republic of Yemen; a war breaks out.
• 1996 – The MV Bukoba sinks in Tanzanian waters on Lake Victoria, killing nearly 1,000.
• 1996 – The Trappist Martyrs of Atlas are executed.
• 1998 – In Miami, Florida, five abortion clinics are hit by a butyric acid attacker.
• 2001 – French Taubira law officially recognizes the Atlantic slave trade and slavery as crimes against humanity.
• 2003 – An earthquake hits northern Algeria killing more than 2,000 people.
• 2005 – The tallest roller coaster in the world, Kingda Ka opens at Six Flags Great Adventure.
• 2006 – The Republic of Montenegro holds a referendum proposing independence from the State Union of Serbia and Montenegro. The Montenegrin people choose independence with a majority of 55%.