King Henry III is captured by his brother-in-law, Simon de Montfort, at the Battle of Lewes.
French King Henri IV (Henri de Navarre) is assassinated by François Ravaillac, a fanatical monk.
English physician Edward Jenner gives the first successful smallpox vaccination.
The Lewis and Clark Expedition officially begins as the Corps of Discovery departs from St. Charles, Missouri.
Union General Nathanial Banks heads towards Port Hudson along the Mississippi River.
""Stars and Stripes Forever" by John Phillip Sousa is performed for the first time in Philadelphia.
Three companies of the 101st Airborne Division fail to push North Vietnamese forces off Hill 937 in South Vietnam.