On This Day: September 21st

War of 1812: British forces abandon their unsuccessful siege of Fort Erie.

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.

French Revolution: The National Convention abolishes the monarchy.

American Revolutionary War: Benedict Arnold gives the British the plans to West Point.

Part of New York City is burned shortly after being occupied by British forces.

A British government army led by Sir John Cope is defeated in less than 15 minutes by the Jacobite forces of Prince Charles Edward Stuart.

The Treaty of Arras is promulgated, causing Burgundy to switch sides in the Hundred Years' War.

Livonian Crusade: The Estonian leader Lembitu and Livonian leader Caupo of Turaida are killed in the Battle of St. Matthew's Day.

Anglo-Norman invasion of Ireland: The Kingdom of Dublin falls to Anglo-Norman invaders.

Emperor Avitus enters Italy with a Gallic army and consolidates his power.