20 May History
- 325 - The Ecumenical council is inaugurated by Emperor Constantine in Nicea.
- 1303 - A peace treaty is signed between England and France.
- 1347 - Cola di Rienzo takes the title of tribune in Rome.
- 1520 - Hernando Cortes defeats Spanish troops sent against him in Mexico.
- 1690 - England passes the Act of Grace, forgiving followers of James II.
- 1674 - John Sobieski becomes Poland's first king.
- 1774 - Parliament passes the Coercive Acts to punish the colonists for their increasingly anti-British behavior. The acts close the port of Boston.
- 1775 - North Carolina becomes the first colony to declare its independence.
- 1784 - The Peace of Versailles ends a war between France, England, and Holland.
- 1799 - Napoleon Bonaparte orders a withdrawal from his siege of St. Jean d'Acre in Egypt.
- 1859 - A force of Austrians collide with Piedmontese cavalry at the village of Montebello, in northern Italy.
- 1861 - North Carolina becomes the last state to secede from the Union.
- 1862 - President Lincoln signs the Homestead Act, providing 250 million acres of free land to settlers in the West.
- 1874 - Levi Strauss begins marketing blue jeans with copper rivets.
- 1902 - The U.S. military occupation of Cuba ends.
- 1927 - Charles Lindbergh takes off from New York for Paris.
- 1930 - The first airplane is catapulted from a dirigible.
- 1932 - Amelia Earhart lands near Londonderry, Ireland, to become the first woman fly solo across the Atlantic.
- 1939 - Pan American Airways starts the first regular passenger service across the Atlantic.
- 1941 - Germany invades Crete by air.
- 1942 - Japan completes the conquest of Burma.
- 1951 - During the Korean War, U.S. Air Force Captain James Jabara becomes the first jet air ace in history.
- 1961 - A white mob attacks civil rights activists in Montgomery, Alabama.
- 1969 - In South Vietnam, troops of the 101st Airborne Division reach the top of Hill 937 after nine days of fighting entrenched North Vietnamese forces.
- 1970 - 100,000 people march in New York, supporting U.S. policies in Vietnam.
20 May Birthdays
- 1663 - William Bradford, printer.
- 1750 - Stephen Girard, American financier and philanthropist.
- 1768 - Dolley Madison, first lady of President James Madison.
- 1799 - Honore de Balzac, French novelist (The Human Comedy, Lost Illusions).
- 1806 - John Stuart Mill, British philospher and economist.
- 1818 - William George Fargo, one of the founders of Wells, Fargo & Co.
- 1882 - Sigrid Undset, Norwegian novelist (Kristin Lavransdatter).
- 1908 - Jimmy Stewart, actor (It's a Wonderful Life, Mr Smith Goes to Washington).