Calendar date · May

What happened on May 21

On May 21, 293: Roman Emperors Diocletian and Maximian appoint Galerius as Caesar to Diocletian, beginning the period of four rulers known as the Tetrarchy.

Events

72

across history

Notable births

50

Notable deaths

50

Zodiac

Gemini

Featured moment · 293

Roman Emperors Diocletian and Maximian appoint Galerius as Caesar to Diocletian, beginning the period of four rulers known as the Tetrarchy.

Diocletian, nicknamed Jovius, was Roman emperor from 284 until his abdication in 305. He was born Diocles to a family of low status in the Roman province of Dalmatia. As with other Illyrian soldiers of the period, Diocles rose through the ranks of the military early in his career, serving under Aurelian and Probus, and eventually becoming a cavalry commander for the army of Emperor Carus.

People

Born on May 21

Elena Huelva 2002– Spanish influencer and writer (2002–2023)
Ivan De Santis 1997– Italian professional footballer
Sisca Folkertsma 1997– Dutch footballer
Viktoria Petryk 1997– Ukrainian singer and songwriter (born 1997)
Kevin Quinn 1997– American actor and singer
Josh Allen 1996– American football player (born 1996)
Indy de Vroome 1996– Dutch tennis player
Karen Khachanov 1996– Russian tennis player (born 1996)
Diego Loyzaga 1995– Filipino actor and model (born 1995)
Show 9 more — notable births on May 21
Tom Daley 1994– English diver (born 1994)
Grete Gaim 1993– Estonian biathlete (born 1993)
Luke Garbutt 1993– English footballer
Matías Kranevitter 1993– Argentine footballer (born 1993)
Lynn Williams 1993– American soccer player (born 1993)
Hutch Dano 1992– American actor
Lisa Evans 1992– Scottish footballer (born 1992)
Philipp Grüneberg 1992– German footballer (born 1992)
Olivia Olson 1992– American actress and singer-songwriter (born 1992)

People

Died on May 21

Gerry Connolly American politician (1950–2025)
Jan A. P. Kaczmarek Polish composer (1953–2024)
Alan Merten American academic administrator (1941–2020)
Rik Kuypers Belgian film director (1925–2019)
Binyavanga Wainaina Kenyan writer and editor (1971–2019)
Nick Menza American drummer (1964–2016)
Annarita Sidoti Italian race walker
Twinkle English singer-songwriter (1948–2015)
Jassem Al-Kharafi Former Kuwaiti Speaker of Parliament
Show 9 more — notable deaths on May 21
Fred Gladding American baseball player (1936–2015)
Louis Johnson American bass guitarist (1955–2015)
Tunku Annuar Tunku Bendahara of Kedah
Johnny Gray American baseball player (1926–2014)
Jaime Lusinchi President of Venezuela from 1984 to 1989
Alireza Soleimani Iranian wrestler (1956–2014)
Count Christian of Rosenborg Danish royal (1942–2013)
Frank Comstock American composer, arranger, conductor, and trombonist
Cot Deal American baseball player (1923–2013)

Timeline

Every May 21 on record

  1. 293 Roman Emperors Diocletian and Maximian appoint Galerius as Caesar to Diocletian, beginning the period of four rulers known as the Tetrarchy.

    Roman emperor from 284 to 305

    Diocletian, nicknamed Jovius, was Roman emperor from 284 until his abdication in 305. He was born Diocles to a family of low status in the Roman province of Dalmatia. As with other Illyrian soldiers of the period, Diocles rose through the ranks of the military early in his career, serving under Aurelian and Probus, and eventually becoming a cavalry commander for the army of Emperor Carus.

  2. 878 Syracuse, Sicily, is captured by the Muslim Aghlabids after a nine-month siege.

    City in Sicily, Italy

    Syracuse is a city and municipality, capital of the free municipal consortium of the same name, located in the autonomous region of Sicily in Southern Italy. As of 2025, with a population of 115,636, it is the fourth most populous city in Sicily, following Palermo, Catania, and Messina.

  3. 879 Pope John VIII gives blessings to Branimir of Croatia and to the Croatian people, considered to be international recognition of the Croatian state.

    Head of the Catholic Church from 872 to 882

    Pope John VIII was the bishop of Rome and ruler of the Papal States from 14 December 872 to his death. He is often considered one of the most able popes of the 9th century.

  4. 996 Sixteen-year-old Otto III is crowned Holy Roman Emperor.

    Holy Roman Emperor from 996 to 1002

    Otto III was the Holy Roman emperor and King of Italy from 996 until his death in 1002. A member of the Ottonian dynasty, Otto III was the only son of Emperor Otto II and his wife Theophanu.

  5. 1349 Dušan's Code, the constitution of the Serbian Empire, is enacted by Dušan the Mighty.

    14th-century Serbian set of laws

    Dušan's Code is a compilation of several legal systems that was enacted by Stefan Uroš IV Dušan of Serbia in 1349. It drew upon Roman law, Byzantine law, as well as elements of customary and canon law. It was used in the Serbian Empire and the succeeding Serbian Despotate.

  6. 1403 Henry III of Castile sends Ruy González de Clavijo as ambassador to Timur to discuss the possibility of an alliance between Timur and Castile against the Ottoman Empire.
  7. 1554 Queen Mary I grants a royal charter to Derby School, as a grammar school for boys in Derby, England.
  8. 1659 In the Concert of The Hague, the Dutch Republic, the Commonwealth of England and the Kingdom of France set out their views on how the Second Northern War should end.
  9. 1660 The Battle of Long Sault concludes after five days in which French colonial militia, with their Huron and Algonquin allies, are defeated by the Iroquois Confederacy.
  10. 1674 The nobility elect John Sobieski King of Poland and Grand Duke of Lithuania.
  11. 1703 Daniel Defoe is imprisoned on charges of seditious libel.
  12. 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.
  13. 1758 Ten-year-old Mary Campbell is abducted in Pennsylvania by Lenape during the French and Indian War. She is returned six and a half years later.
  14. 1792 A lava dome collapses on Mount Unzen, near the city of Shimbara on the Japanese island of Kyūshū, creating a deadly tsunami that killed nearly 15,000 people.
  15. 1799 The end of the Siege of Acre (1799): Napoleon Bonaparte abandons his siege of the Ottoman city of Acre after two months. This was the turning point of Bonaparte's Egyptian campaign and one of the first major defeats he suffered in his military career.
Show 15 earlier entries from May 21
  1. 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.
  2. 1851 Slavery in Colombia is abolished.
  3. 1856 Lawrence, Kansas is captured and burned by pro-slavery forces.
  4. 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.
  5. 1864 Russia declares an end to the Russo-Circassian War and many Circassians are forced into exile. The day is designated the Circassian Day of Mourning.
  6. 1864 American Civil War: The Battle of Spotsylvania Court House ends.
  7. 1864 The Ionian Islands reunite with Greece.
  8. 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.
  9. 1871 Opening of the first rack railway in Europe, the Rigi Bahnen on Mount Rigi.
  10. 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.
  11. 1881 The American Red Cross is established by Clara Barton in Dansville, New York.
  12. 1894 The Manchester Ship Canal in the United Kingdom is officially opened by Queen Victoria, who later knights its designer Sir Edward Leader Williams.
  13. 1904 The Fédération Internationale de Football Association (FIFA) is founded in Paris.
  14. 1911 President of Mexico 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, concluding the initial phase of the Mexican Revolution.
  15. 1917 The Imperial War Graves Commission is established through royal charter to mark, record, and maintain the graves and places of commemoration of the British Empire's military forces.

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