September 21

455 – Emperor Avitus enters Rome with a Gallic army and consolidates his power. 1170 – The Kingdom of Dublin falls to Norman invaders. 1217 – Livonian Crusade: The Estonian leader Lembitu and Livonian leader Kaupo the Accursed are killed in the Battle of St. Matthew's Day. 1435 – The Congress of Arras causes Burgundy to switch sides in the Hundred Years' War. 1745 – A Hanoverian army is defeated, in ten minutes, by the Jacobite forces of Prince Charles Edward Stuart 1776 – Part of New York City is burned shortly after being occupied by British forces. 1780 – American Revolutionary War: Benedict Arnold gives the British the plans to West Point. 1792 – French Revolution: The National Convention abolishes the monarchy. 1809 – British Secretary of War Lord Castlereagh and Foreign Secretary George Canning meet in a duel on Putney Heath, with Castlereagh wounding Canning in the thigh. 1843 – The crew of schooner Ancud, led by John Williams Wilson, takes possession of the Strait of Magellan on behalf of the Chilean government. 1860 – Second Opium War: An Anglo-French force defeats Chinese troops at the Battle of Palikao. 1896 – Anglo-Egyptian conquest of Sudan: British forces under the command of Horatio Kitchener take Dongola. 1898 – Empress Dowager Cixi seizes power and ends the Hundred Days' Reform in China. 1921 – A storage silo in Oppau, Germany, explodes, killing 500–600 people. 1933 – Salvador Lutteroth establishes Mexican professional wrestling. 1934 – A large typhoon hits western Honshū, Japan, killing more than 3,000 people. 1938 – The Great Hurricane of 1938 makes landfall on Long Island in New York. The death toll is estimated at 500–700 people. 1939 – Romanian Prime Minister Armand Călinescu is assassinated by the Iron Guard. 1942 – The Holocaust in Ukraine: On the Jewish holiday of Yom Kippur, Nazis send over 1,000 Jews of Pidhaitsi to Bełżec extermination camp. 1942 – The Holocaust in Ukraine: In Dunaivtsi, Ukraine, Nazis murder 2,588 Jews.