WHAT HAPPENED ON 23. SEPTEMBER
Want to find out what all happened on 23. September

Pope Callixtus II and Holy Roman Emperor Henry V agree to the Concordat of Worms to put an end to the Investiture Controversy. (23. September 1122)

The Battle of Arnemuiden was the first naval battle of the Hundred Years' War and the first naval battle using artillery, as the English ship Christofer had three cannon and one hand gun. (23. September 1338)

Battle of Kherlen, the second significant victory over Ming China by the Mongols since 1368. (23. September 1409)

Battle of Blore Heath, the first major battle of the English Wars of the Roses, is fought at Blore Heath in Staffordshire. (23. September 1459)

Spanish naval forces rout an English fleet, under the command of John Hawkins, at the Battle of San Juan de Ulúa near Veracruz. (23. September 1568)

The Merchant Royal, carrying a treasure worth over a billion US dollars, is lost at sea off Land's End. (23. September 1641)

First commencement exercises occur at Harvard College. (23. September 1642)

American Revolution: John Paul Jones on board the USS Bonhomme Richard wins the Battle of Flamborough Head. (23. September 1779)

American Revolution: British Major John André is arrested as a spy by American soldiers exposing Benedict Arnold's change of sides. (23. September 1780)

Second Anglo-Maratha War: Battle of Assaye between the British East India Company and the Maratha Empire in India. (23. September 1803)

Lewis and Clark return to St. Louis after exploring the Pacific Northwest of the United States. (23. September 1806)

Tripolitsa, Greece, is captured by Greek rebels during the Greek War of Independence. (23. September 1821)

The Knickerbockers Baseball Club, the first baseball team to play under the modern rules, is founded in New York. (23. September 1845)

Astronomers Urbain Jean Joseph Le Verrier, John Couch Adams and Johann Gottfried Galle collaborate on the discovery of Neptune. (23. September 1846)

Grito de Lares ("Lares Revolt") occurs in Puerto Rico against Spanish rule. (23. September 1868)

Nintendo Koppai (Later Nintendo Company, Limited) is founded by Fusajiro Yamauchi to produce and market the playing card game Hanafuda. (23. September 1889)

American Asiatic Squadron destroys a Filipino battery at the Battle of Olongapo. (23. September 1899)

Norway and Sweden sign the "Karlstad treaty", peacefully dissolving the Union between the two countries. (23. September 1905)

University of Alberta in Alberta, Canada, is founded. (23. September 1908)

The Phantom of the Opera (original title: Le Fantôme de l'Opéra), a novel by French writer Gaston Leroux, is first published as a serialization in Le Gaulois. (23. September 1909)